Q  P 
141 


U.C.  B 


RAIT 


BIOL 


B    3    37^    173 


APM-li-iV 

• 

AN  EXPERIMENTAL  STUDY 

OF  HUNGER  IN  ITS 
RELATION  TO  ACTIVITY 


By 
TOMI  WADA,  A.M. 


Submitted  in  partial  fulfillment  of  the  requirements  for  the 

degree  of  Doctor  of  Philosophy,  in  the  Faculty  of 

Philosophy,  Columbia  University 


REPRINTED  FROM 

ARCHIVES  OF  PSYCHOLOGY 

R.    S.    WOODWORTH,    EDITOR 

No.  57 


NEW  YORK 
JUNE,  1922 


AN  EXPERIMENTAL  STUDY 

OF  HUNGER  IN  ITS 
RELATION  TO  ACTIVITY 


By 
TOMI  WADA,  A.M. 


Submitted  in  partial  fulfillment  of  the  requirements  for  the 

degree  of  Doctor  of  Philosophy,  in  the  Faculty  of 

Philosophy,  Columbia  University 


REPRINTED  FROM 

ARCHIVES  OF  PSYCHOLOGY 

R.    S.    WOODWORTH,    EDITOR 

No.  57 


NEW  YORK 
JUNE,  1922 


a-3 


CONTENTS. 

Chapter  Page 

I.     Introduction   and  General  Description  of  the   Present    Study.  .        5 

1.  Introduction                .             .            .-        '.            ..           .    .  .5 

2.  Main   Purposes          ...            .            .            .            .  „        7 

3.  The  Apparatus           .         .   .            ,.           .            .            .  .        8 

4.  The    Subjects             .            .            .           ..            .            .    .  .10 

5.  The  Main  Experiments       .           .            .            .            .  .11 

II.     Nature  of   Hunger          .    '        .            .            .            .            .  .12 

1.  Hunger   Mechanism              .            .            .            .            .  .12 

2.  Activities  of  the  Stomach  .            ...            .            .  .13 

III.  Correlation    of    the    Hunger    Rhythm    with    Other    Physiological 

Conditions       .            .            .            .            ...            .  .23 

1.  Respiration     .            .            .            .            ...         ,  .  .23 

2.  Vasomotor  Volume  .            .            .  •      w    .            .            .  .23 

3.  Salivary  Secretion     .        ,-   .  >          .        .    . "          .        •-  .  .      23 

IV.  Correlation  of  the  Hunger  Rhythm  with  the  Sensation  of  Hunger      24 
V.     Correlation  of  the   Hunger   Rhythm  with   Bodily  Activities  .      27 

1.  Bodily  Movements  of  Men  During  Sleep            .            .  .27 

2.  Correlation  of  the  Hunger  Rhythm  with  Bodily  Movements 

of  Men  During  Sleep         „           .            .            .            .  .      27 

3.  Correlation  of  the  Hunger  Rhythm  with  Bodily  Movements 

of  Men  During  Waking  State      .            .            .            .  .30 

4.  Bodily  Movements  of  Infants         .            .            .  .31 

5.  Bodily  Movements  of  Albino  Rats          .            .            .  .32 
VI.     Correlation  of  the  Hunger  Rhythm  with  Dreaming          •   »  .      33 

VII.     Correlation  of  the  Hunger  Rhythm  with  Motor  Activity     .  .      35 

VIII.     Correlation  of  the  Hunger  Rhythm  with  Mental  Activity  .  .      45 

IX.     The  Effects  of  Various  Stimuli  upon  the  Hunger  Rhythm  .       54 

1.  The  Effect  of  Mechanical  Stimulation      .            .-            .  .54 

2.  The  Effect  of  Drugs           .            .            .          "  .    -        .  .56 

3.  The  Effect  of  Conscious  Effort,  Thought,  Sight,  Smell  and 

Taste  of  Food          .            .            .           .'           .           .  .58 

4.  The  Effect  of  Nausea  from  Rotation       .            .            .  .59 

5.  The  Effect  of  Electric  Shocks        .        ...            :,            .-  .       60 

6.  The  Effect  of  Prolonged  Work     .            .            .            .  .60 

7.  The  Effect  of  Reading  Exciting  Stories  .            .           ...  .61 

X.     Conclusions            ...  62 


5078"i 


PREFACE 

The  present  study  of  hunger  and  activity  was  undertaken  at 
the  psychological  laboratory  of  Johns  Hopkins  Hospital,  first 
in  the  summer  of  1920,  and  more  systematically,  from  February, 
1921,  to  February,  1922.  Owing  to  the  fact  that  it  is  a  new  field 
of  work  for  the  psychological  laboratory,  and  especially,  that 
it  was  a  new  field  for  the  experimenter,  numerous  trials  and 
errors  were  made.  Though  further  researches  are  eagerly  h'oped 
for  and  needed  along  this  line,  it  is  encouraging  that  this  one  and 
a  half  year's  experimentation  yielded  certain  definite  results, 
which  are  presented  in  the  following  pages. 

ACKNOWLEDGMENTS 

Acknowledgments  are  due  to  Professor  Edward  L.  Thorn- 
dike  for  guidance  given  to  the  writer  in  the  study  of  general 
psychology  as  preparation  for  the  present  experiment,  and 
for  his  introduction  of  the  writer  to  the  psychological  laboratory 
of  Johns  Hopkins  Hospital.  The  author's  gratitude  is  sin- 
cerely expressed  to  Dr.  Arthur  I.  Gates,  whose  encouragement 
and  advice  were  immeasurable.  Special  acknowledgment  is  due 
to  Dr.  Curt  P.  Richter  of  Johns  Hopkins  Hospital  for  his 
valuable  suggestions  and  assistance.  To  the  parents  of  the  two 
babies  the  author  feels  great  gratitude  and  admiration  for  their 
sacrificial  interest  in  the  scientific  work  and  the  privileges  given 
to  the  writer.  To  Professor  R.  S.  Woodworth  for  the  present 
publication,  and  to  Miss  Caroline  Stackpole,  Miss  Marian  Bene- 
dict, and  Miss  Mary  Evenden,  who  corrected  the  English,  and  to 
other  people  who  assisted  the  present  work  by  becoming  sub- 
jects or  by  reading  manuscript  and  proof,  acknowledgment  is 
gratefully  made. 

TOMI  WADA. 
June,  1922. 


CHAPTER  I. 
1.    INTRODUCTION. 

The  need  to  understand  the  fundamental  drives  of  human  be- 
havior is  tremendously  increasing  in  these  years  of  social  unrest, 
economic  readjustment,  and  educational  reformation. 

Pointing  out  the  lack  of  understanding  as  to  the  fundamental 
urges  of  labor  problems,  the  late  Mr.  Carleton  Parker1  says  that 
the  laborers'  philosophy  is  a  stomach  philosophy,  and  their  political  in- 
dustrial revolt  is  a  hunger  riot.  Indeed,  hunger  is  one  of  the  strongest 
of  human  urges.  "On  the  same  plane  with  pain  and  the  dominant  emo- 
tions of  fear  and  rage  as  agencies  which  determine  the  action  of  the 
organism,  is  the  sensation  of  hunger,"  says  Cannon2.  "It  is  a 
sensation  so  peremptory,  so  disagreeable,  so  tormenting,  that 
men  have  committed  crimes  in  order  to  assuage  it.  It  has  led 
to  cannibalism,  even  among  the  civilized.  It  has  resulted  in 
suicide.  That  dull  ache,  or  gnawing  pain,  referred  to  the  lower 
midchest  region  and  the  epigastrium,  may  take  imperious  control 
of  human  actions."2  Plunger  not  only  compels  the  striped 
muscles  to  seek  food,  but  urges  man  and  animals  to  fight,  and 
even  to  risk  life  itself.  Hunger  is  such  a  strong  drive  that 
the  term  itself  stands  as  a  representative  of  all  wishes  and 
desires.  'When  the  effort  to  satisfy  hunger  is  thwarted,  the  whole 
organism  reacts  to  the  situation,  or  the  thwarting  agent,  with 
such  hyper-tension  of  all  organs  and  muscles  and  fibres  that  the 
excitement  may  lead  to  various  types  of  defensive  behavior. 
Moreover,  as  McDougall3  says  that  all  instinctive  impulses  may, 
with  opposition  or  obstruction,  give  place  to,  or  are  complicated 
by,  the  pugnacious,  or  combative,  impulse  directed  against  the 
source  of  the  obstruction.  Thus  hunger  may  become  a  dynamic 
force  of  destructive  or  constructive  emotions  and  behaviors. 

In  the  primitive  type  of  man,  hunger  plays  such  a  role  that  the 
greater  part  of  his  daily  activity  is  directed  by  it.  Food  was 
the  first  form  of  property.  The  value  of  things  was  measured 
in  terms  of  food.  "Primitive  migration  was  always  after  food, 
food  for  men  and  food  for  cattle,  which  in  turn  was  food  for 
men."4  Ceremonials,  religion,  manners  and  laws  grew  in  close  rela- 
tion with  food.  Food  was  the  first  thing  desired  and  fought  for. 

1  Parker,    Carleton;    Casual   Laborer  and   Other   Essays,    1920. 

2  Cannon,  W.   B.;   Bodily   Changes   in   Pain,    Hunger,   Fear   and   Rage.     1920.   P.    232. 

3  McDougall,    Wm.;    Introduction    to    Social    Psychology.    1908.    P.    72. 
"Hall,  G.  S.;  Adolescence. 


6  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

The  earliest  education  and  habit  formation  of  children  begin 
also  with  regard  to  food.  Psychological  tendencies,  such  as 
acquisition,  pugnacity,  rivalry,  jealousy,  sympathy  and  gratitude 
display  themselves  in  connection  with  food,  and  more  or  less 
"condition"  or  determine  the  future  character  of  the  child.  Thus 
food  is  a  matter  of  great  concern  in  infancy  and  childhood.  Ex- 
cept when  in  need  of  food,  a  healthy  infant  is  asleep.  With  the 
onset  of  hunger  the  sleeping  baby  awakes,  wriggles  and  cries. 
If  food  is  not  given  him  he  struggles  more  and  more.  His  eyes 
wide  open,  his  mouth  moving  or  chewing  anything  at  hand, 
he  cries  with  all  his  might,  hands  clinched  tight,  face  red, 
hot,  and  often  perspiring,  legs  kicking,  or  drawn  up  tightly  to  his 
body.  Often,  too,  his  back  is  bent,  and  stretched.  The  whole 
organism  is  struggling.  G.  Stanley  Hall5  says,  "the  true  be- 
ginning of  a  psychology  essentially  genetic  is  hunger,  the  first 
sentient  expression  of  the  will  to  live."  This  must  be  the  "Elan 
Vital." 

As  soon  as  food  is  given,  the  infant  sucks  it  with  such  power 
that  often  he  cannot  wait  to  breathe.  The  whole  organism  is  in  a 
state  of  readiness  and  tension.  The  swallowing  reflex  takes 
place  as  soon  as  any  particle  is  placed  on  the  tongue.  Very  soon 
food  and  sucking  are  coupled  together,  and  this  becomes  an  es- 
tablished habit.  But  before  that,  all  kinds  of  efforts  and  errors 
are  made  to  satisfy  this  great  drive  of  hunger.  We  often  see 
babies  chewing  the  edge  of  a  blanket,  and  more  often,  their  own 
fingers. 

In  animal  psychology  it  is  a  well  known  fact  that  rats,  chickens, 
cats,  and  dogs  do  not  take  any  interest  in  solving  puzzle  cage 
problems  unless  they  are  hungry.  The  varying  food  habits  and 
hunger  behaviors  of  different  species  of  animals  are  very  inter- 
esting in  relation  to  their  environment.  As  Rogers6  did  in  1916, 
Pavlov7  recently  proved  by  the  following  experiment  that  a 
greater  part  of  the  alimentary  center  is  situated  below  the 
cerebro-hemisphere,  and  controls  hunger  behavior,  more  or  less 
independently  of  the  central  nervous  system.  "A  decerebrated 
pigeon  remains  immovable  for  hours  in  the  middle  of  an  abundance  of 
food,  being  incapable  of  feeding  itself.  However,  in  such  a  pigeon, 
the  activity  of  the  alimentary  center  manifests  itself  clearly. 

5  Hall,  G.   S.;  Adolescence 

6  Rogers,   F.   T. ;   The  Hunger   Mechanism  of  the  Pigeon   and   its  Relation  to  the   Central 
Nervous  System.    Am.  Jour.  Physiol.,  Vol.  XLI. 

7  Pavlov,  J.  P.;  Sur  le  centre  de  la  faim.    Jour,   de  Psychologic.    April,    1921. 


IN  ITS  RELATION  TO  ACTIVITY  7 

We  nourish  him,  and  he  takes  the  grains  in  his  beak.  Five  or 
six  hours  after  the  meal,  the  animal  begins  to  stir,  walk  about, 
and  becomes  more  and  more  active.  It  is  easy  to  be  convinced 
that  it  is  the  alimentary  center  that  provokes  that  agitation.  In 
order  that  he  may  again  become  immovable  for  a  long  time,  it 
is  sufficient  to  catch  the  pigeon  and  make  him  swallow  a  suffi- 
cient quantity  of  grains."  Thus  even  when  there  is  no  cortical 
control,  hunger  leads  to  a  greater  degree  of  motility  on  the  part 
of  the  animal  capable  of  locomotion,  and  to  a  greater  degree  of 
activity  of  the  feeding  reflex.  Even  among  the  lowest  types 
of  unicellular  animals  and  plants,  that  possess  no  nervous  sys- 
tem, hunger  manifests  itself  strongly  enough  to  cause  visibly 
increased  motility  and  cell  excitability. 

2.  MAIN  PURPOSES. 

What  can  we  say  about  the  influence  that  hunger  exerts  upon 
the  activities  of  human  beings?  It  is  said  that  hunger,  even 
during  sleep,  dominates  and  often  controls  the  nature  of  dreams 
and  if  strong  enough  awakes  the  sleeper.  Is  this  true?  What  is 
the  effect  of  hunger  upon  muscular  and  mental  work?  Biolo- 
gists say  that  fish,  that  are  going  against  a  river  current,  and 
butterflies,  that  are  undergoing  great  physical  exertion,  never 
feed.8  It  is  a  common  practice  among  students  and  business  men 
to  eat  but  little  when  there  is  important  mental  work  to  be  done. 
Does  hunger  have  any  influence  even  upon  the  specialized  func- 
tions that  are  measured  by  intelligence  tests?  What  is  the  in- 
fluence of  emotional  states  upon  hunger?  Some  animals  refuse 
food,  when  in  captivity,  even  to  the  point  of  starvation  in  the 
presence  of  plenty.  Do  men  feel  the  same  way  in  great  emo- 
tional excitement?  Such  are  the  problems  to  be  discussed  in  the 
following  experiments. 

We  owre  valuable  guidance  in  studying  "instinct"  to  William 
James9.  "The  older  writings  on  instinct  are  ineffectual  waste 
of  words,  because  their  authors  never  came  down  to  this  definite 
and  simple  point  of  view,  but  smothered  everything  in  vague 
wonder  at  the  clairvoyant  and  prophetic  power  of  the  animals." 
He  says,  "The  strict  physiological  way  of  interpreting  the  facts 
leads  to  far  clearer  results."  Such  was  the  method  employed  in 
the  present  experiment. 

8  Carlson,  A.  J.;   The  Control  of  Hunger  in  Health  and  Disease.    1917.   P.   8. 
8  James,   Wm.;    Principles   of   Psychology.     1890.     Pp.    383-385. 


8  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

3.  THE  APPARATUS. 

1.  A  Stomach  Tube.   For  the  purpose  of  registering  the  activ- 
ity of  the  stomach,  a  very  thin  rubber  balloon  of  flexible  quality, 
4  cm.  in  diameter,  and  from  12  to  13  cm.  in  length,  was  chosen. 
This  balloon  was  connected  with  a  rubber  tube  of  3  mm.  diameter 
and  of  any  desired  length.  A  very  small  metal  tube  was  inserted 
at  one  end  of  this  tube,  and  the  rubber  balloon  was  tied  over  it 
with  silk  thread.     The   metal   tube   made   the   connection   firm, 
yet  did  not  close  the  rubber  tube.     A  little  rubber  cement  was 
used  in  order  to  have  the  rubber  balloon  attached  firmly  and 
smoothly,  so  that  the  edges  of  the  balloon  would  not  irritate  the 
throat,  when  the  subject  swallowed  it.    A  number  of  such  stom- 
ach tubes  were  kept  ready.     They  were  disinfected  before  use, 
and  were  kept  in  running  water,  in  order  to  preserve  the  good 
quality  of  the  rubber. 

When  the  air  was  sucked  out,  the  balloon  and  the  tube  were 
very  small,  and  could  easily  be  swallowed.  Infants  usually 
swallow  them  even  more  easily  than  adults. 

2.  A   Recording   Apparatus.     This   apparatus    consisted   of   a 
U  tube  2.5  cm.  in  diameter  and  22  cm.  in  height,  half  filled  with 
water.  One  limb  of  this  manometer  had  a  floating  marker  which 
consisted  of  a  thin  cork,  an  aluminum  plate  12  cm.  long  and  2  mm. 
wide,  with  a  thin  celluloid  flag  on  top  of  it,  and  a  cork  adjuster 
on  the  upper  end  of  the  U  tube.     The  other  limb  of  the  mano- 
meter had  a  rubber  cork  from  which  a  rubber  tubing  reached  to  a 
glass  bottle  17  cm.  high.     (See  Figure  1.) 

When  the  subject  was  in  the  desired  position,  he  swallowed 
the  tube,  which  was  connected  with  the  recording  apparatus. 
The  other  end  of  the  stomach  tube  was  connected  with  another 
rubber  balloon  of  the  same  kind  (B),  which  was  enclosed  in  a 
glass  bottle  (D).  The  experimenter  blew  through  the  adjoining 
tube  (C),  which  distended  the  balloons  in  the  stomach  and  in  the 
bottle  and  then  closed  it  with  a  clamp.  The  air  pressure  in  the 
bottle  forced  the  water  up  in  one  limb  of  the  U  tube  (E),  and 
forced  up  a  floating  marker  (F).  The  experimenter  opened  the 
clamped  tube  (G),  and  let  the  air  escape  until  the  water  in  the 
manometer  was  at  the  same  level  on  both  limbs,  and  closed  it 
again  with  the  clamp.  Every  change  in  pressure  on  the  balloon 
in  the  stomach  registered  on  the  smoked  paper  of  a  kymograph. 
This  method  had  certain  distinct  advantages  over  those  previous- 
ly used.  Others  connected  the  stomach  tube  directly  with  the 


ITS  RELATION  TO  ACTIVITY 


manometer.  The  result  was  that  the  air  pressure  in  the  balloon 
kept  the  manometer  water  unequal.  Consequently  the  apparatus 
lost  sensitivity.  By  the  method  here  employed,  the  level  of  the 
water  in  each  limb  was  the  same  at  the  beginning  of  the  experi- 
ment and  hence  sensitivity  was  increased. 

Another  method  employed  in  the  present  experiment  was  to 
use  a  double  rubber  stomach  balloon  between  the  layers  of 
which  a  bismuth  coat  was  inlaid.  Observations  through  a  fluoro- 
scope  made  it  possible  to  locate  the  exact  position  of  the  balloon 
in  the  stomach.  When  the  balloon  was  inflated,  the  movements 
of  the  stomach  could  easily  be  observed,  since  the  bismuth  is 
opaque  to  the  X-rays. 


Fig.   1.    The  Apparatus. 

(A)  A  stomach  balloon,  swallowed  into  the  stomach.  (B)  A  balloon  con- 
nected with  the  stomach  and  enclosed  in  the  bottle.  (C)  An  adjoining  clamped 
tube,  to  blow  in  the  air.  (D)  A  bottle  to  adjust  the  air  pressure.  (E)  A 
manometer  of  U  tube.  (F)  A  floating  marker.  (G)  A  clamped  tube  at  the 
bottom  of  the  bottle.  (H)  A  tambour  registering  activities  on  the  bed. 

3.  In  order  to  register  the  gross  bodily  activities  of  a  man  or 
an  infant  during  the  day  or  night,  a  tambour  5y2  cm.  (2% 
inches)  in  diameter,  and  2l/±  cm.  (i/§  in.)  in  depth  was  used. 
This  tambour  was  covered  with  a  rubber  dam  of  good  quality 
and  fairly  thick.  A  thin  metal  disc,  3  cm.  (Ij/g  in.)  in  diameter 
was  shellacked  in  the  middle  of  the  rubber  membrane,  and  on  this 
disc  a  2  cm.  (%  in.)  flat-headed  wooden  screw,  with  the  pointed 
end  up,  was  attached  by  means  of  wax.  Fairly  elastic  wire  was 


10  AN  EXPERIMENTAL  STUDY  OF.  HUNGER 

made  into  a  loose  spring  about  four  inches  in  height.  One  end  of 
this  spring  was  tied  with  cord  to  the  stem  of  the  wooden  screw,, 
while  the  other  end  was  attached  loosely  to  the  bottom  of  a  spring  bed. 
By  means  of  a  clamp  on  one  leg  of  the  bed,  the  tambour  was  sup- 
ported, and  at  the  same  time  xan  be  adjusted  according  to  the 
weight  of  the  subject,  so  as  to  keep  the  tambour  at  the  maximum  of 
sensitivity.  The  rubber  tube  from  the  bottom  of  the  tambour 
was  connected  to  a  Marey  tambour  to  register  the  body  move- 
ment on  the  smoked  paper.  In  earlier  experiments,  from  three 
to  ten  tambours  were  used,  distributed  at  different  points  of 
the  bed.  But  experience  showed  that  one  in  the  proper  position 
was  just  as  sensitive,  if  not  more  so.  (Fig.  1.  H.)  For  the  experi- 
ments with  infants,  the  tambour,  without  the  adjusting  wire 
spring,  in  direct  contact  with  the  bottom  of  the  baby  bed,  or  carriage,. 
was  found  more  sensitive. 

4.  The  kymograph  that  was  used  was  the  extension  kymo- 
graph, on  which  paper  7  feet  10.5  inches  (94.5  in.)  long  could  be 
placed.  A  speed  of  20  inches  per  hour  was  usually  used.  Faster 
and  slower  speeds  were  tried,  with  the  result  that  this  speed 
was  found  to  be  the  most  accurate  and  convenient.  Every  4^4 
hours  changes  of  paper  had  to  be  made.  When  the  experiment 
was  carried  on  throughout  the  night  the  paper  had  to  be  changed 
only  once,  at  midnight. 

4.  THE  SUBJECTS. 
.  T.  W.,  a  woman  student  in  psychology. 

Subject  C.  P.  R.,  a  research  man  in  psychology. 

Subjects  H.  R.  B.,  T.  W.  C.,  and  H.  E.  H.  were  graduate  stu- 
dents in  medicine  in  Johns  Hopkins  University.  All  of  them 
were  healthy,  vigorous  young  men. 

Patient  Z.,  a  young  woman,  in  the  Phipps  psychiatry  clinic, 
suffering  from  chronic  hypochondria. 

Patient  Y.,  a  young  man  of  the  clinic,  suffering  from  gen- 
eral weakness  and  inability  to  work. 

Baby  Ann  R.,  born  February  13,  1921.  She  was  nine  months 
old,  weighing  18  pounds,  at  the  time  of  the  experiment,  which 
was  conducted  from  November  to  January,  1922. 

Baby  Barbara  P.,  born  on  November  10,  1921,  was  one  month 
old  when  the  experiment  was  begun  on  December  28th.  She 
weighed  11  pounds  9  ounces  at  the  end  of  the  experiment.  Feb- 
ruary 2,  1922. 

Sixty  Albino  rats,  of  different  sex  and  ages,  were  under  the 


IN  ITS  RELATION  TO  ACTIVITY  11 

writer's  care  from  April  to  June,  1921.     Observations  on  other 
rats  were  made  also. 

5.  THE  MAIN  EXPERIMENTS. 

The  first  set  of  experiments  here  presented  concern  them- 
selves with  the  nature  of  hunger.  Neurological  study  of  the 
autonomic  and  the  sympathetic  nervous  systems  was  carried 
on,  as  well  as  anatomical  study  of  these  systems,  and  of  the 
stomach  muscles.  The  dynamic  phases  of  the  problem  were 
studied  by  direct  measurement  of  the  activity  of  the  stomach. 
Varying  forms  of  stomach  activity  were  recorded  on  smoked 
paper  by  means  of  a  special  apparatus.  The  frequency  and  dura- 
tion of  contraction  periods  were  studied.  The  results  presented 
in  Chapter  II  show  the  general  facts  concerning  stomach  activity. 

The  next  step,  described  in  Chapter  III,  is  to  find  the  correla- 
tion between  hunger  states  and  other  physiological  conditions, 
especially  in  respiration,  vasomotor  changes,  and  salivary  secre- 
tion flow. 

The  third  experiment,  recorded  in  Chapter  IV,  is  to  determine 
the  sensation  of  hunger  and  its  relation  to  hunger  contractions. 

Chapter  V  introduces  the  measurement  of  the  gross  bodily 
movements  of  men  during  sleep.  These  results  were  analyzed 
and  compared  with  the  results  of  similar  experiments  tried 
during  the  day.  The  experiments  were  extended  to  infants, 
whose  activities  were  measured  during  the  day  and  night.  Fi- 
nally rats  were  subjected  to  general  observation. 

Mental  activity  during  sleep  was  studied  through  the  experi- 
ments with  dreams  which  are  presented  in  Chapter  VI. 

Experiments  to  ascertain  if  there  is  augmentation  of  muscular 
work  by  himger  contractions  are  presented  next,  in  Chapter  VII. 
The  hand  dynamometer  measurements  were  correlated  with  the 
hunger  states. 

Chapter  VIII  deals  with  the  correlation  of  hunger  states  with 
mental  work  in  Thorndike  mental  examinations. 

Chapter  IX  discusses  the  results  obtained  from  a  series  of 
experiments  in  which  various  stimuli  were  introduced.  Me- 
chanical stimuli,  drugs  alleged  to  have  power  to  relax  smooth 
muscles,  conscious  effort,  the  thought,  sight,  and  smell  of  food, 
were  given.  These  results  throw  light  on  the  origin  and  control 
of  hunger  contractions.  Stimuli  of  still  stronger  kinds,  such  as 
electric  shocks,  rotation,  prolonged  work  and  reading  exciting 
stories  were  introduced,  and  the  effects  of  these  activities  upon 
hunger  states  were  measured. 


12  AN  EXPERIMENTAL  STUDY  OF  HUNGER 


CHAPTER  II. 

THE  NATURE  OF  HUNGER. 
1.  HUNGER  MECHANISM. 

1.  A  Brief  Description  of  the  Stomach. 

The  stomach  is  a  pear  shaped  organ,  situated  in  the  epigastric 
region  of  the  body,  with  three  chief  parts,  the  fitndus,  the  body, 
and  the  pyloric  portion,  which  is  located  at  the  right  extremity  of 
the  stomach.  The  region  where  the  oesophagus  enters  is  known  as 
the  cardiac,  and  the  junction  with  the  intestine  is  called  the  pylorus. 

The  musculature  of  the  stomach  consists  of  non-striated  fibres 
of  three  kinds,  namely,  the  longitudinal,  or  outer  layer,  the  circular 
layer,  and  the  middle  layer.  The  middle  layer  is  lined  by  the  sub- 
mucous  coat,  and  finally  by  the  mucous  coat. 

2.  Nervous  Control  of  the  Stomach. 

It  is  generally  maintained  that  the  vagi  nerves  are  the  main  afferent 
pathway  for  the  hunger  impulses.  The  vagi  nerves  have  their  nuclei 
in  the  fasciculus  solitarius,  in  the  medulla.  The  efferent  vagi  motor 
fibres  come  to  the  stomach  from  medulla  nuclei.  There  are  reasons 
for  believing  that  the  vagi  and  the  sympathetic  (splanchnic)  nerves, 
which  come  from  the  coeliac  ganglion,  regulate  the  tonus  of  the 
stomach,  one  as  accelerator,  and  the  other  as  inhibitor.  Some  main- 
tain that  both  nerves  have  accelerating  and  inhibiting  fibres  in  them- 
selves. Experiments  have  been  repeatedly  made  to  show  that  when 
either  the  vagi  or  the  splanchnic  nerves  are  cut,  separately,  or  both 
together,  the  stomach  keeps  its  movements  without  much  disturbance. 

There  are  some  other  nerve  fibres,  such  as  the  plexus  of  Meissner, 
between  the  submucous  layers,  and  the  plexus  of  Auerbach,  between 
the  longitudinal  and  circular,  muscular  layers.  These  intrinsic  plexus 
seem  to  be  capable  of  maintaining  the  movement  of  the  musculature, 
independently  of  the  extrinsic  nerve.*  The  real  origin  of  the 
gastric  hunger  contractions  is  not  yet  definitely  established.  Some 
maintain  the  myogenic  theory,  and  some  the  neurogenic  theory  of 
the  intrinsic  plexuses.  Chemical  changes  in  the  blood  also  has  been 
considered  as  a  possible  cause  of  the  gastric  contractions.  Though 

*  Muller,    L.    R.;    Das   Vegetative   Nervensystem.    1920.    Pp.    127-134. 


IN  ITS  RELATION  TO  ACTIVITY  13 

the  periodicity  of  the  hunger  rhythm  and  the  abrupt  cessation  of 
the  contraction  periods  do  not  parallel  with  the  fact  that  the  chemical 
or  starvation  changes  in  the  blood  are  more  continuous,  yet  the 
hypothesis  can  not  be  altogether  abandoned.  Especially,  such  an 
internal  secretion  as  that  of  adrenalin  may  act  with  certain  periodicity 
upon  the  stomach  walls  and  the  intrinsic  nerve  plexuses  and  start  the 
hunger  contractions  at  the  same  time  this  chemical  change  is  affecting 
the  other  parts  of  the  organism. 

3.     Hunger  Contractions  Versus  Digestive  Contractions. 

Howell*  says  that  the  chief  difference  in  character  between  the 
digestive  and  the  hunger  contractions  seems  to  lie  in  the  fact  that 
the  former  involves  mainly  the  antral  end,  while  the  latter  are  de- 
scribed as  starting  from  the  region  of  the  cardiac  orifice,  spreading 
as  peristalic  waves  over  the  whole  stomach. 

Digestive  movements  occur  a  few  minutes  after  the  entrance  of 
food.  Small  contractions  start  in  the  middle  region  of  the  stomach 
and  run  to  the  pylorus.  The  fundus  end  of  the  stomach  is  not  actively 
concerned  with  these  movements,  but  serves  rather  as  a  reservoir 
for  the  food,  while  the  muscular  pyloric  region  is  the  apparatus  that 
triturates  and  macerates  the  food,  and  forces  it  out  from  time  to 
time  into  the  duodenum.  Hunger  contractions  start  in  the  cardiac 
end  of  the  stomach,  and  proceed  towards  the  fundic  region.  Gradu- 
ally the  contraction  waves  cover  a  larger  and  larger  space.  From 
A  lay  10th  to  14th  observations  were  made,  through  a  fluoroscope, 
of  the  stomach  movements  of  the  young  woman  patient,  Z.  From 
May  18th  to  20th  a  young  man,  Subject  Y.,  was  under  observation. 
These  observations  verified  the  above  statement  of  the  activities  of 
the  stomach,  its  advancing  waves,  and  the  portions  involved. 

2.  ACTIVITIES  OF  THE  STOMACH. 

By  means  of  the  above  mentioned  apparatus  the  writer  measured 
the  activities  of  the  stomach.  When  the  apparatus  was  very  delicate 
the  following  typical  states  were  recorded: 

1.  The  respiration  pressure  rhythm.  When  the  stomach  is  in 
atonic  condition  there  is  no  movement  at  all.  Consequently  the  record 
shows  only  respiration.  Almost  uniform  ups  and  downs  on  the 
level  are  to  be  seen,  as  shown  in  Figure  2.  This  complete  atonic 
condition  is  very  rare  except  immediately  after  vigorous  contractions, 
or  after  a  little  water  is  taken. 

*  Howell;   A  Text   Book  of  Physiology.    1921,   P.    721. 


14  AN  EXPERIMENTAL  STUDY  OF  HUNGER 


Fig.  2.    The  respiration  pressure  rhythm. 

2.  The  pulse  pressure  rhythm.  When  the  respiration  is  held  for 
a  few  seconds,  or  when  the  stomach  pressure  gets  so  low  that  the 
floating  marker  goes  down  to  the  limit  and  does  not  record  respira- 
tion, the  pulse  rhythm  is  recorded.  (See  Fig.  3.) 


Fig.  3.    The  pulse  rate  rhythm. 

3,  The  tonus  rhythm.  The  stomach  is  usually  in  tonus  condition, 
and  often  with  tonus  waves  of  great  uniformity.  (See  Fig.  4.) 
These  tonus  contractions  of  the  fundus  gradually  increase  in  ampli- 
tude, as  well  as  in  rate.  (See  Fig.  5  A,  B,  C.) 


Fig.  4.    The  tonus  rhythm. 

4.     The  powerful  hunger  contractions.     Gradually  increased  tonus 
reaches  to  the  hunger  contractions.    The  duration  of  this  contraction 


IN  775*  RELATION  TO  ACTIVITY 
Fig.  5.     A.,  B.  and  C. 


15 


A.    Beginning  of  tonus  rhythm. 


B.    Gradual  increase  of  amplitude  of  tonus  rhythm. 


C.    Gradual  change  of  rate  and  amplitude  of  tonus  rhythm. 


16  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

is  usually  from  30  to  40  seconds.  (See  Fig.  6.)  The  recorded 
amplitude  of  the  contractions  depends  upon  the  size  of  the  stomach 
balloon  and  of  the  manometer,  as  well  as  upon  the  extent  to  which 
the  balloon  is  distended.  In  the  present  experiment,  however,  these 
factors  were  controlled  so  as  to  be  as  constant  as  possible.  Quite 
often  records  reached  to  twelve  centimeters  in  amplitude,  the  maximum 
of  the  apparatus.  Contractions  were  still  more  powerful,  and  pushed 
the  marker  to  the  top,  and  water  kept  running  over  the  manometer 
for  some  minutes. 


Fig.  6.    The  contraction  rhythm. 

5.  The  tetanus  ending.  The  powerful  hunger  contractions  some- 
times end  with  tetanus,  or  prolonged  contractions.  (See  Fig.  7.) 
This  is  especially  the  case  with  prolonged  starvation.  After  the 
strong  contractions,  an  abrupt  drop  into  atonic,  or  weaker  tonus. 
conditions,  often  follows.  (See  Fig.  8.) 

The  strength  of  the  hunger  contractions  may  be  measured  in  terms 
of  the  amount  of  water  pushed  up  by  the  gastric  pressure.  A  con- 
traction that  recorded  a  height  of  one  inch  on  the  smoked  paper  pushes 
20cc.  of  water  in  a  U  tube  of  which  diameter  was  2.5  cm.  The 
strongest  contraction  that  the  apparatus  could  record  was  5  inches 
in  amplitude,  which  had  power  to  push  up  100  cc.  of  water. 

Tables  I  and  II  contain  results  of  experiments  during  the  night 
and  the  day.  They  explain  the  duration  of  quiescence  and  tonus, 
the  number  and  duration  of  contraction  periods,  and  the  amplitude 
of  the  contractions.  (See  Figs.  9,  10.) 


IN  ITS  RELATION  TO  ACTIVITY 


17 


Fig.  7.    The  tetanus  ending. 


Fig.  8.    The  abrupt  drop  from  contraction  to  quiescence. 

Distribution  of  these  different  states  of  activity  varies  a  great  deal 
according  to  the  individual's  general  physical  condition,  his  rate  of 
metabolism,  caused  by  physical  and  mental  work,  and  his  food  habits. 
However,  a  rough  average  of  all  records  show  the  following  features : 


18 


AN  EXPERIMENTAL  STUDY  OF  HUNGER 


bfi 

to 


IN  ITS  RELATION  TO  ACTIVITY 


19 


from  2  to  3  hours  after  a  meal  there  appear  tonus  waves  which  last 
from  30  minutes  to  one  hour.  They  increase  in  amplitude  and  rate, 
and  become  gradually  stronger  contractions.  An  average  number  of 
the  contractions  is  between  20  and  40  during  a  period  which  extends 
from  30  to  60  minutes. 


20 


AN  EXPERIMENTAL  STUDY  OF  HUNGER 


TABLE  I. 
Showing  the  Activity  of  the  Stomach  for  Various  Subjects  During  the  Night. 


Duration 
Time                 of 

Duration 
of 

Contraction 

Duration 
of 

Aver.   Amp. 
of 

No. 
of 

Date 

Subj.     Started       Quiescence 

Tonus 

Period 

Contrac. 

Contrac. 

Contrac. 

1921 

Mar.  23 

B          10:40            :40min. 

:35  min. 

12:15-12:30 

:15  min 

1.5  in, 

6 

:30 

1:00-  1:30 

:30 

2. 

12 

:30 

:30 

4:15-   5:45 

:30 

3.25 

15 

:45 

:15 

5:30-  6:15 

:45 

2. 

6 

Mar.  24 

B         10:30         2:15 

2:00 

3:45.  4:45 

1:00 

4.25 

40 

5:15-  5:30 

:15 

2. 

8 

Mar.  25 

B         11:30 

:20 

11:50-12:10 

:20 

1.25 

12 

12:25-12:45 

:20 

1.50 

10 

JOS 

12:55-   1:25 

:30 

1.50 

32 

:45 

2:05-  2:55 

:50 

2.5 

49 

"1  5 

3:20-  3:55 

:35 

1.5 

20 

i30 

4:00-  4:40 

:40 

3. 

31 

Apr.  13 

B         10:30           :15 

2:45 

1:30-  2:00 

:30 

1.5 

10 

1:45 

3:15-  3:30 

'1  5 

1.75 

10 

4:15-  4:45 

•30 

3.75 

23 

6:30-  6:45 

:15 

2.75 

10 

:15 

:45 

Apr.  20 

B         10:30           :30 

1:30 

:30 

2:00-  2:30 

:30 

2.5 

19 

1:30 

5:10-  5:15 

:15 

2. 

15 

5.30-  5:45 

:15 

3.75 

22 

:30 

6:30-  7:00 

•30 

4. 

18 

7:00-  7:30 

:30 

4.5 

19 

Mar.  25 

H         10:45 

1:20-  1:35 

•15 

2 

7 

1:45-  2:20 

":35 

2. 

15 

:10 

3:45-  4:15 

:30 

4.25 

20 

4:30-  5:00 

:30 

3. 

9 

Mar.  28 

H         11:00 

Mar.  30 

H          10:30            :30 

1:15 

12:15-12:30 

:15 

2. 

10 

:45 

1:15-  1:30 

:15 

2. 

12 

.  15 

1:45-  2:15 

:30 

3. 

14 

:20 

2:30-  2:45 

•15 

3.25 

11 

:30 

4:10-  4:30 

140 

3.5 

18 

4:45-  5:15 

:30 

3.5 

8 

•15 

:15 

5:15-  5:45^ 

1:00 

4.5 

21 

June  10 

H         11:50           :30 

12:30-  1:15 

:45 

2. 

30 

:30 

1:35-  1:40 

:05 

2. 

8 

:20 

2:00-  2:30 

:30 

2. 

15 

2:30-  3:15 

:45 

4.5 

45 

:45 

:25 

4:25-  5:30 

1:05 

5. 

47 

:45 

6:20-  6:50 

:30 

5. 

25 

June  11 

H          11:19            :30 

:30 

1:00-  3:20 

2:20 

4.5 

145 

:30 

4:00-  4:30 

:30 

3.5 

26 

•30 

5:10-  5:25 

•  1  5 

4. 

18 

:45 

6:10-  7:10 

lioo 

4.5 

45 

June     7 

C          11:10 

2:00 

1:00-   1:30 

:20 

2.5 

20 

1:40-  2:00 

:20 

2.25 

16 

•30 

:30 

4:30-  4:50 

:20 

4.5 

16 

:30 

5:30-  6:00 

:30 

3.5 

19 

1:00 

:15 

7:40-  8:00 

:20 

2.5 

16 

June     8 

C         11:50 

1:15 

:30 

1:30-  2:30 

1:00 

3. 

40 

1:30 

4:00-  5:00 

1:00 

2.5 

40 

:30 

:10 

5:30-  6:10 

:40 

3,5 

34 

•20 

6:40-  7:00 

:20 

3. 

7 

7:05-  7:20 

:15 

2. 

8 

June     9 

C         11:50           :30 

1:00-  1:25 

:25 

2. 

41 

:45 

:20 

2:20-  2:30 

:  10 

2. 

11 

2:45-  2:55 

:10 

2.5 

9 

•10 

3:05-  3:10 

•05 

2. 

7 

•20 

3:30-  4:15 

:45 

2. 

30 

4:20-  5:00 

:40 

5. 

43 

:30 

•15 

5:45-  6:10 

:25 

3. 

28 

•20 

6:30-  7:10 

3.5 

32 

•35 

IN  ITS  RELATION  TO  ACTIVITY 


21 


TABLE  II. 
Showing  the  Activity  of  the  Stomach  for  Various  Subjects  During  the  Day. 


Time 

Duration 
of 

Duration 
of 

Contraction 

Duration 
of 

Aver.    Amp. 
of 

No. 

Date 

Subj.     Started 

Quiescence 

Ton  us 

Period 

Contrac. 

Contrac. 

Contrac. 

1920 

July  30 

W           3:35 

3:40-  4:15 

:35  min 

3.  in. 

12 

:05 

4:30-  5:00 

:30 

3. 

20 

:30 

5:45-  6:25 

:40 

3. 

21 

:30 

:45 

8:00-  8:30 

:30 

3. 

19 

:20 

8:50-  9:40 

:50 

3. 

J2 

1921 

Apr.     10 

B          10:30 

:10 

2:00 

:  10 

1:00 

Ir30-  1:45 

:15 

2.5 

9 

1:00 

1:00 

4:20-  4:30 

•10 

2 

8 

:30 

5:00-  5:50 

:50 

3.5 

31 

1:00 

lune     6 

B           9:45 

1:00 

1:00 

11:30-11:40 

:10 

3. 

3 

Apr.     9 

H           3:40 

:10 

:10 

4:10-  4:30 

:20 

1.0 

15 

:10 

•10 

4:50-  5:15 

:25 

1.5 

22 

:15 

:20 

5:50-  6:20 

:30 

1.5 

25 

Apr.   14 

H           4:40 

:30 

:30 

5:40-  5:45 

:05 

2.5 

2 

Apr.   18 

H           4:30 

•10 

:30 
:20 

5:00-  5:30 

:30 

2.5 

26 

1:00 

Apr.  22 

H           5:00 

:10 

5:10-  5:50 

:40 

3.5 

25 

l!20 

Apr.  24 

H           9:00 

1:00 

:20 

9:00-  9:30 

:30 

4.5 

16 

11:20-11:35 

:  15 

4.2 

14 

:45 

12:35-12:50 

:15 

4.2 

12 

:40 

':30 

3:00-  3:15 

:15 

4.2 

16 

:30 

•15 

2:00 

1:00 

5:30-  6:00 

:30 

4. 

17 

1:00 

:30 

Apr.  26 

H           4:40 

:30 

:30 

5:00-  5:15 

:15 

2.7 

15 

1:30 

May      8 

H           9:00 

:30 

:20 

1:25 

12:00-12:30 

:30 

2. 

15 

12:45-  1:25 

:45 

4.5 

28 

:35 

•30 

2:30-  2:45 

:15 

2. 

12 

:45 

3:30-  3:40 

:  10 

1.5 

6 

:50 

4:45-  5:00 

:15 

2.5 

17 

1:00 

May  21 

H           4:00 

:20 

4:20-  4:50 

:30 

2. 

28 

:20 

5:10-  5:40 

:30 

2.5 

25 

:15 

5:55-  6:10 

:15 

2. 

12 

June     9 

H           9:00 

-.30 

2:30 

12:00-12:40 

:40 

3. 

27 

:20 

1:20-  1:55 

:35 

4.5 

22 

1:00 

1:35 

4:30-  5:00 

:30 

3.5 

21 

:15 

5:15-  6:00 

:45 

4.5 

34 

Apr.     3 

C          11:30 

2:20 

1:20-   1:30 

•10 

2. 

6 

1:00 

:50 

3:30-  3:50 

':20 

2  2 

11 

1:10 

5:00-  6:00 

1:00 

3.5 

52 

Apr.   15 

C           4:15 

1:15 

:45 

2.2 

3 

Apr.   16 

C           3:30 

1:00 

1:30 

Apr.   17 

C          10:15 

:30 

•10 

11:10-11:40 

:30 

3. 

20 

1:30 

!30 

1:10-  1:25 

:15 

3. 

14 

Apr.   19 

C           4:20 

1:00 

:30 

22  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

TABLE  II.  (Continued) 


Date 

1921 

Subj. 

Time 
Started 

Duration 
of 
Quiescence 

Duration 
of 
Tonus 

Contraction 
Period 

Duration 
of 
Contrac. 

Aver.    Amp. 
of 
Contrac. 

No. 
Contrac. 

Apr.  21 

C 

4:55 

:30 

5:30-  5:40 

•10 

4. 

10 

:30 

:30 

5:10-  5:55 

145 

4.2 

21 

Apr.  23 

C 

1:30 

:30 

:30 

1:30-  2:10 

:40 

3.5 

46 

2:45-  3:20 

3. 

42 

:20 

:20 

4:00-  6:10 

2:10 

3.7 

22 

Apr.  25 

C 

4:33 

:45 

5:30-  5:40 

:10 

2. 

7 

:20 

5:45-  6:00 

:15 

2.5 

13 

:45 

Apr.  27 

C 

6:52 

:30 

:30 

May  15 

C 

10:05 

1:00 

1:00 

1:00 

:20 

1:20-   1:40 

:20 

2. 

12 

1:00 

2:40-  3:00 

:20 

3. 

16 

:20 

4:30-  5:00 

:30 

2. 

3 

June     5 

C 

1:45 

:40 

1:30 

5:15-  5:45 

:30 

3. 

26 

June     7 

C 

9:30 

1:35 

:15 

11:20-11:45 

:25 

2 

18 

:25 

;  JO 

IN  ITS  RELATION  TO  ACTIVITY  23 


CHAPTER  III. 

CORRELATION  OF  THE  HUNGER  RHYTHM   WITH 
OTHER  PHYSIOLOGICAL  CONDITIONS. 

1.  RESPIRATION. 

The  stomach  balloon  registers  very  sensitively  the  effect  of  respira- 
tion upon  the  stomach.  Another  method  of  measuring  respiration 
on  the  chest  by  means  of  Marey's  pneumograph  was  tried  on  Subject 
C  from  1 :45  to  6  P.  M.  on  June  4th.  All  results  show  that  there  was 
no  specially  deep  or  shallow  breathing  at  the  time  of  the  contraction. 

2.  VASOMOTOR  VOLUME. 

For  four  hours  a  record  of  the- glass  plethysmograph  on  the  right 
arm  of  Subject  C  was  taken  simultaneously  with  that  of  the  stomach. 
In  periods  of  tonus  conditions  of  the  stomach,  the  rhythms  of  the 
plethysmograph  record  correlate  closely  with  the  ups  and  downs  of 
the  tonus.  The  vasomotor  changes  shown  in  the  plethysmograph 
records  looked  as  if  they  followed  closely  the  ups  and  downs  of  the 
stomach  record.  But  the  powerful  hunger  contraction  waves  did  not 
correspond  to  the  rhythm  of  vasomotor  changes  recorded  "by  the 
plethysmograph. 

3.  SALIVARY  SECRETION. 

In  the  experiment  on  July  30th,  Subject  W  went  through  a  twenty 
hour  starvation  period.  On  the  occurrence  of  each  contraction  period 
there  was  an  abundant  secretion  of  saliva.  Her  mouth  became  so 
filled  with  the  secretion  that  she  had  to  expectorate  several  times.  This 
never  happened  in  quiescent  periods.  An  improved  method  of  regis- 
tering the  salivary  flow  of  Stenson's  duct  was  devised  by  Dr.  C.  P. 
Richter,  together  with  the  present  writer,  by  joining  to  the  metal  can- 
nula  for  collecting  secretion,  a  long,  narrow  glass  tube,  which  was 
placed  on  a  yard  stick.  The  measurement  of  air  bubbles  through  the 
tube  was  recorded  as  the  secretion  flowed.  By  using  this  method,  to- 
gether with  the  stomach  tube,  one  can  measure  the  correlation  between 
the  salivary  secretion  and  the  state  of  hunger.  Owing  to  the  dis- 
comfort of  keeping  both  pieces  of  apparatus  in  the  mouth  for  a  long 
time,  this  experiment  was  abandoned. 


24  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

In  the  experiment  of  conditioning  salivary  secretion  to  the  sound 
of  a  bell,  by  using  carbolic  acid,  lemon  juice  and  chocolate,  it  was 
found  that  immediately  after  a  meal  conditions  were  unfavorable 
for  the  experiment  because  little  saliva  could  be  obtained  for  several 
hours.  Pavlov  reports  an  experiment  by  Nikifrovsky,  of  retarded 
conditioned  reflex  of  the  salivary  secretion  of  a  dog.  Introduction 
of  acid  solution  three  minutes  after  the  appearance  of  a  strong  light 
was  repeated,  so  as  to  establish  this  three  minutes'  retarded  con- 
ditioned reflex.  "It  is  at  5  P.  M.  that  we  distribute  food  to  our  dogs : 
if  we  make  an  experiment  of  retarded  reflex  at  10  A.  M.,  salivary 
secretion  does  not  appear  until  the  end  of  three  minutes.  But  if  we 
bring  over  the  same  experiment  at  3  or  4  P.M.  we  cannot  obtain 
the  retardation."  This  fact  shows  that  the  gland  is  more  ready  to 
secrete  saliva  when  the  dog  is  hungry.  Thus  Pavlov  points  out  the 
close  relation  between  the  salivary  secretion  center  and  the  hunger 
center.  It  is  a  common  observation  that  people  have  abundant  saliva 
in  the  mouth  when  they  are  hungry.  The  writer's  experience  agrees 
with  the  statement  of  Carlson*  that  there  is  a  rhythm  of  the  salivary 
flow  parallel  to  the  gastric  hunger  contraction  rhythm.  He  goes 
further  to  say  that  each  hunger  contraction  is  accompanied  by  a  brief 
gush  of  saliva  from  the  duct. 


CHAPTER  IV. 

CORRELATION  OF  THE  HUNGER  RHYTHM  WITH 
THE  SENSATION  OF  HUNGER. 

The  apparatus  was  so  arranged  that  the  subject  pressed  an  electric 
magnetic  button,  which  registered  the  appearance  of  the  sensation 
of  hunger.  At  the  same  time,  the  activity  of  the  stomach  was  re- 
corded. This  is  the  well  known  Cannon- Washburn  experiment,  and 
was  repeated  in  the  present  study  only  to  confirm  the  result. 

On  April  23rd,  Subject  C  came  to  the  laboratory  at  1:15  P.M., 
without  luncheon,  and  his  sensation  of  hunger  was  recorded  in  the 
above  mentioned  way.  The  experiment  was  carried  on  up  to  6  P.  M. 
He  pressed  the  button  at  three  different  contraction  periods,  as  fol- 
lows: 10  signals  at  the  3:20  contraction  period,  5  at  4:10,  and  6  at 
4:50.  All  of  the  signals  occurred  at  the  height  of  a  contraction. 
No  sensation  of  hunger  was  recorded  at  quiescent  periods. 

*  Carlson,   A.   J.;   "Control   of   Hunger  in   Health  and  Disease".    1916.    Pp.  90-91. 


ITS  RELATION  TO  ACTIVITY 


25 


be 

£ 


26  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

Subject  H  underwent  the  same  experiment,  on  April  24th,  for 
9l/2  hours,  starting  at  9  A.  M.  His  record  was  as  follows:  6  signals 
at  11 :30,  a  tonus  period,  2  at  12,  at  the  beginning  of  a  contraction 
period,  4  signals  at  1,  at  the  end  of  the  contraction  period,  5  at  1 :25, 
4  at  1 :35,  both  in  tonus  periods,  and  4  signals  at  5  :30,  at  the  height 
of  contractions. 

These  results  show  that  the  sensation  of  hunger  occurred  simul- 
taneously with  the  contraction  of  the  stomach.  However,  observa- 
tions made  in  these  experiments  showed  that,  when  the  contraction 
became  chronic  from  lack  of  food  for  several  hours,  the  sensation 
became  diffused,  and  the  subject  failed  to  appreciate  each  hunger  con- 
traction. In  the  first  case  of  the  above  mentioned  experiments,  Sub- 
ject C  had  one  long  continuous  contraction  period,  from  4  to  6  P.  M. 
He  signaled  only  11  times  at  the  heights  of  the  largest  contractions, 
while  the  number  of  contractions  counted  over  140. 

This  experiment  was  repeated  on  May  16th  with  a  young  woman 
patient,  Z.,*  whose  complaint  was  that  she  was  never  hungry  because 
her  stomach  was  weak  and  could  not  digest  any  food.  She  lay  down 
on  a  bed,  and  pressed  a  button  in  the  same  way  as  the  other  subjects. 
The  experiment  was  started  at  10  A.  M.  She  had  a  contraction 
period  from  10:20  to  11:30,  and  another  one  at  12:35,  which  con- 
tinued until  2:10,  lasting  one  hour  and  thirty-five  minutes.  These 
contractions  were  of  great  amplitude  and  recurred  rapidly.  In  this 
case  of  incessant  and  chronic  contractions,  also,  the  patient  failed 
to  perceive  some  of  the  weaker  contractions. 

Patient  Y.,  a  young  man,  was  the  subject  of  this  experiment  on 
May  17th  and  20th.  He  had  morning  and  noon  hunger  contraction 
periods.  He  discriminated  each  sensation  of  hunger  at  the  height 
of  each  contraction. 

A  sensation  of  dull  weakness,  headache,  and  sometimes  of  nausea, 
is  felt  when  the  hunger  pang  is  left  unsatisfied  for  a  long  time.  This 
seems  to  vary  greatly  in  different  individuals.  Within  the  knowledge 
of  the  writer,  some  individuals  say  that  they  never  had  a  hunger  pang 
in  their  life,  while,  on  the  other  hand,  others  speak  of  having  had, 
at  times,  so  strong  a  hunger  pang  in  the  epigastric  region  that  they 
could  not  sit  still,  but  had  to  go  out  to  get  something  to  eat. 

The  origin  of  the  sensation  of  hunger  was  thus  established  as 
being  the  muscular  contractions  of  the  stomach. 


*  This    experiment    and    some    others    following    were    made    possible    by    the    co-operation 
with  Dr.   C.  P.  Richter. 


IN  ITS  RELATION  TO  ACTIVITY  27 


CHAPTER  V. 

• 

CORRELATION  OF  THE  HUNGER  RHYTHM   WITH 
BODILY  ACTIVITIES. 

1.  BODILY  MOVEMENTS  OF  MEN  DURING  SLEEP. 

From  March  9th  on,  every  night  for  a  week,  Subject  R  slept  on 
the  bed  that  registered  all  his  bodily  movements  during  sleep.  The 
stomach  tube  was  not  employed  in  this  study.  The  tambour  system 
was  made  so  sensitive  that  even  his  finger  movements  were  registered 
at  the  beginning  of  the  experiments.  The  results  were  studied  by 
putting  on  a  chart  the  number  of  body  movements  made.  It  was 
found  that  the  activities  fell  into  distinct  groups,  and  that  these 
groups  came  with  certain  periodicity.  Figure  12  shows  a  part  of 
the  periodical  groups  of  the  activities.  Another  interesting  discovery 
was  that,  when  the  subject  had  taken  a  glass  of  milk  before  going  to 
bed,  he  was  much  less  active  in  the  early  part  of  the  night  than  when 
he  went  to  bed  feeling  hungry,  but  without  the  milk.  Compare 
Fig.  B,  which  is  the  record  of  the  night  when  he  had  the  milk,  with 
C  and  D  in  Fig.  12.  These  facts  suggested  the  possible  correlation 
between  stomach  activity  and  general  bodily  activity. 

2.  CORRELATION  OF  HUNGER  RHYTHM  WITH  BODILY  MOVEMENTS 
OF  MEN  DURING  SLEEP. 

A  second  group  of  experiments  was  started  on  March  23rd  when 
the  subject  had  become  thoroughly  accustomed  to  swallowing  the 
stomach  tube.  Subject  B  swallowed  the  tube  and  then  went  to  bed 
in  one  of  the  quiet  rooms  of  the  laboratory,  where  the  ventilation 
and  heating  were  favorable.  The  tubings  from  the  bottom  of  the 
bed,  together  with  that  from  the  stomach,  were  led  through  a  hole 
in  a  thick  door  into  the  next  room,  where  the  experimenter  adjusted 
them  to  the  recording  apparatus.  The  machine  operated  throughout 
the  night  without  disturbing  the  sleep  of  the  subject.  Fig.  13  shows 
the  results.  The  subject  had  dinner  at  6  P.  M.,  studied  until  10:30 
and  then  came  to  the  laboratory  to  have  the  experiment  started  at 
10:45.  The  stomach  was  in  a  quiescent  state  for  one-half  hour,  then 
it  gradually  began  to  have  more  and  more  tonus  rhythm.  At  12:15 
there  appeared  some  bodily  movements,  none  of  which  had  appeared 
hitherto.  At  12:30  the  experimenter  observed  that  the  body  move- 


28 


AN  EXPERIMENTAL  STUDY  OF  HUNGER 


Fig.  12.    The  gross  bodily  movements  in  quantitative  measurement. 

merits  occurred  simultaneously  with  the  stomach  contractions.  A 
few  minutes  later  the  stomach  fell  again  into  the  quiescent  period, 
only  to  resume  a  tonus  condition  within  fifteen  minutes.  The  second 
contraction  period  began  five  minutes  before  1  A.  M.  Most  of  the 
body  movements  occurred  at  the  heights  of  stomach  contractions. 


IN  ITS  RELATION  TO  ACTIVITY 


29 


30  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

There  were  two  more  definite  contraction  periods  at  4:15-45,  and 
5:30-6:30.  At  the  end  of  the  last  contraction  the  subject  got  up 
of  his  own  accord,  and  the  experiment  was  stopped.  The  subject 
said  that  he  had  slept  well,  without  discomfort  from  the  swallowed 
tube.  The  experiment  was  repeated  on  the  following  five  nights. 
With  slight  modifications,  bodily  activities  of  men  during  sleep  were 
recorded  on  thirteen  nights.  Photographs  of  actual  records  testify 
to  the  simultaneous  occurrence  of  the  bodily  activities  and  hunger 
contractions.  (See  Fig.  13.) 


3.  CORRELATION  OF  THE  HUNGER  RHYTHM  WITH  BODILY 
MOVEMENTS  OF  MEN  DURING  WAKING  STATE. 

On  April  23rd  a  record  of  the  bodily  movements  of  Subject  C 
during  the  day  was  taken.  He  had  eaten  nothing  since  breakfast. 
At  1:15  P.M.  the  experiment  was  started,  the  subject  lying  on  a 
.couch,  and  reading  "Moon  Calf."  He  had  contraction  periods  from 
1 :30  to  2:10,  and  from  2:45  to  3:20,  also  from  4  to  6:10.  Bodily 
activities  occurred  almost  simultaneously  with  the  stomach  contrac- 
tions, as  in  the  night  experiments.  (See  Fig.  14.) 


Fig.  14.    Bodily  movements  of  men  during  waking  state. 

On  May  8th,  Subject  H  had  no  breakfast,  and  was  experimented  on 
from  9  A.  M.  to  6  P.  M.  in  the  same  way.  He  had  the  following 
contraction  periods:  12-12:30,  12:45-1:25,  2:30-2:45,  3:30-3:40, 
4 :45-5  :00  P.  M.  There  were  numerous  bodily  movements  during 
the  contraction  periods,  while  practically  none  of  them  appeared  at 
quiescent  times.  Since  this  was  a  whole  day  experiment,  with  five 
contraction  periods,  the  result  was  confirmatory  in  showing  rhythm- 
ical activity  periods  during  the  day,  when  the  subject  was  relatively 
free  from  external  stimuli. 


7Af  ITS  RELATION  TO  ACTIVITY  3i 

4.   BODILY  MOVEMENTS  OF  INFANTS. 

The  tambour  apparatus  was  so  set  underneath  a  small  bed  as  to 
register  the  bodily  activity  of  Baby  Ann.  From  November  9th,  the 
night  activities  were  taken.  It  was  necessary  to  have  a  baby  whose 
feeding  habits  were  regular.  Baby  Ann  had  been  brought  up  under 
ideal  conditions.  Since  she  was  ten  months  old  her  feeding  periods 
had  remained  unchanged.  They  were  as  follows:  7:30  to  8  A.M., 
11 :30  to  12  M.,  3:30  to  4  P.  M.,  and  8:30  to  9  P.  M.  She  received 
8  ounces  at  the  first  feeding,  then  10  ounces,  again  10  ounces  and  at 
the  last  feeding  8  ounces  of  milk.  She  was  put  to  bed  at  9  P.  M. 
in  a  quiet  nursery,  and  was  not  touched  until  the  morning  feeding 
period.  Records  show  very  marked  periodicity  of  activity;  about 
once  in  forty-five  minutes  she  wriggled  in  her  sleep,  and  towards 
morning  activity  increased,  but  without  changing  the  periodicity. 
These  experiments  were  repeated  for  ten  nights  and  the  results  con- 
firmed the  periodicity.  (Fig.  15.) 


Fig.  15.    Activities  of  infants.     Baby  Ann    (9  months  old), 
during  the  night.     11  P.  M.— 8  A.M. 

Baby  Barbara  slept  in  a  carriage  instead  of  a  crib.  The  tambour, 
which  was  placed  underneath  the  body  of  the  carriage,  registered 
the  baby's  activity  sensitively.  Since  she  was  very  young  there  was 
no  marked  difference  between  the  activities  of  day  and  night.  She 
slept  on,  excepting  when  she  was  fed  at  6:30  and  10:30  A.  M.,  and 
at  2 :30,  6 :30  and  10 :30  P.  M.  For  some  time  after  the  night  feeding 
the  baby  was,  according  to  the  record,  very  quiet.  At  intervals  of 
about  once  every  40  minutes,  she  made  bodily  movements  which  in- 
creased in  frequency  and  vigor  toward  the  morning  until  the  next 
feeding,  which  came  at  6:30. 

These  periods  depend  upon  the  quantity  and  quality  of  food  given, 
as  well  as  upon  the  health  conditions  and  the  digestive  capacity  of  the 
child.  However,  we  may  well  predict  regular  activity  periods  as  the 
time  for  feeding  draws  near.  In  the  case  of  Baby  Ann,  change  of  diet 
by  a  small  amount  of  oatmeal  and  orange  juice  in  the  course  of  the 
ten  day  experiment  did  not  affect  the  activity  and  hunger  periods. 
As  the  age  increases  food  habits  change,  and  consequently,  the  bodily 
activity  periods.  * 


32  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

Day  activity  records  were  taken  for  three  consecutive  days.  The 
infant  Ann  was  kept  in  the  nursery  with  several  toys,  while  any  out- 
side stimulus,  such  as  a  sight  of  the  parents,  was  avoided.  The  feeding 
periods  were  strictly  kept.  The  results  showed  that  the  day  activities 
also  fell  in  periods  of  about  45  minutes. 

5.   BODILY  MOVEMENTS  OF  ALBINO  RATS. 

About  200  Albino  rats  were  kept  in  the  laboratory  for  observation 
and  experimentation.  Some  60  white  rats  were  under  the  writer's 
care  and  observation  from  April  to  June,  1921.  Thirty  of  them  were 
3  weeks  old,  and  15  were  3  months  old,  while  the  rest  were  5  months 
of  age  in  April.  About  l/$  of  each  group  were  females.  They  were 
kept  in  cages  and  fed  once  a  day  at  12  M.  Their  hunger  behaviors 
were  closely  observed.  At  the  time  of  feeding,  the  rats  appeared 
to  be  extremely  hungry.  The  young  ones,  especially,  pushed  each 
other  at  the  gate,  climbed  on  top  of  each  other,  and  jumped  up  and 
down  on  the  wire  cloth  of  the  cage.  The  older  ones  sniffed  and 
smelled  the  milk,  and  bit  the  wire  at  the  gate  with  their  teeth.  After 
the  trial  in  the  maze,  they  were  provided  with  food,  which  made 
them  more  excited.  They  fought,  they  screamed,  and  finally  they 
snatched  away  a  piece  of  bread  and  ate  it  most  eagerly.  After  they 
ate  enough,  some  of  them  would  take  pieces  away  from  others  and 
pile  them  up  in  a  corner,  often  under  the  saw  dust.  The  older  ones 
would  go  to  the  nook  and  sleep,  while  the  young  ones  played  and 
ran  after  each  other  for  a  while  and  then  would  take  a  nap.  Even  the 
older  ones  woke  up  several  hours  after  the  feeding,  and  the  activities 
of  the  rats  gradually  increased  toward  the  next  feeding  period.  By 
the  measurement  of  his  rats,  Dr.  Richter1  found  that  the  free 
activities  of  the  rats  came  with  certain  periodicity.  To  the  bottom  of  a 
triangular  cage  were  affixed  three  tambours  which  registered  on  the 
smoked  paper  by  means  of  tubing  all  the  activities  of  a  rat.  When 
the  rat  was  kept  in  a  quiet  and  dark  room,  spontaneous  activities 
fell  in  definite  groups.  Until  about  7  days  after  birth,  records  showed 
no  definite  periodicity.2  Activities  were  quite  constant.  But  after 
a  rat  had  been  fed  sufficiently  to  keep  it  from  getting  hungry  for  a 
time,  it  would  not  feed  for  about  30  minutes.  Thus,  on  the  7th  day, 
the  record  began  to  show  periodicity.  There  was  a  definitely  active 
period  about  once  every  30  minutes.  As  the  size  of  the  rat,  as  well 
as  the  stomach  increased,  these  periods  came  less  frequently — once 

1  Richter,  C.  P.;  Behavioristic  Study  of  the  Activity  of  the  Rat.    1922. 

2  The    author    was    permitted    to   mention    some    part    of    the    unpublished    experiment    by 
Mr.  G.  H.  Wang. 


IN  ITS  RELATION  TO  ACTIVITY  33 

every  40  to  50  minutes,  but  the  amount  of  activity  became  greater. 
The  rat  often  became  very  vicious  when  hungry.  Very  old  rats, 
however,  were  observed  to  be  much  less  active,  and  less  frequently 
active. 

A  suitable  stomach  balloon  was  made,  and  several  trials  were 
made  to  measure  the  stomach  activity  of  a  rat.  On  April  30th, 
the  stomach  tube  was  successfully  put  in  a  large  sized  and  very 
tame  rat.  But  the  rat  made  every  possible  effort  to  pull  the  tube  out. 
Under  such  abnormal  conditions  it  was  impossible  to  secure  any 
good  record,  except  a  faint  respiration  mark. 

Nevertheless  the  correspondence  of  hunger  and  activity  periods 
of  white  rats  under  laboratory  conditions  is  rendered  very  probable 
by  the  above  results. 

CHAPTER  VI. 

CORRELATION  OF  THE  HUNGER  RHYTHM 
WITH  DREAMING. 

The  extent  to  which  the  gastric  hunger  contraction  affects  the 
mental  status  of  the  sleeping  man  was  investigated  in  connection  with 
dreaming. 

On  June  8th,  Subject  C  came  to  the  laboratory  having  had  dinner 
at  6  o'clock.  At  11 :50  P.  M.  he  went  to  sleep  with  the  stomach  tube. 
At  1 :30  A.  M.  there  was  a  contraction  period  lasting  an  hour.  At 
2:20  A.  M.,  that  is,  at  the  end  of  the  contraction  period,  the  experi- 
menter opened  the  door  quietly  and  asked  the  subject  if  he  had 
dreamed.  The  answer  was,  "I  wasn't  dreaming."  At  4  A.  M.  there 
was  another  contraction  period  lasting  one  hour.  At  4 :25  A.  M. 
the  subject  was  asked  the  same  question,  concerning  dreaming.  "Not 
that  I  know  of,"  was  the  answer.  From  5  :30  to  6:10  and  from  6:40 
to  7 :00  and  from  7 :05  to  7 :20,  there  were  contraction  periods,  but 
no  question  was  asked. 

June  9th.  Subject  C.  The  contraction  periods,  as  follows :  From 
1  :00  A.  M.  to  1 :25,  2:20  to  2:30,  3:05  to  3:10  and  from  3:30  to 
4:15.  From  4:20  to  5:00,  5:45  to  6:10,  6:30  to  7:10.  At  4:15  in 
the  contraction  period,  Subject  C  was  asked  about  dreams.  He 
answered,  "I  had  a  dream,  but  have  forgotten  it."  At  7:10  the 
answer  was  "Not  that  I  know  of." 

June  10th,  Subject  H  starting  experiment  at  11:50  P.M.,  had 
contraction  periods  from  12:30  A.M.  to  1:15,  from  1:35  to  1:40, 
from  2:00  to  2:30,  from  2:30  to  3:15  and  from  4:25  to  5:30.  At 
4 :45  he  was  asked  the  question  about  dreaming.  It  was  ten  seconds 


34  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

before  the  subject  was  sufficiently  awake  to  answer.  He  said  that 
he  had  dreamed  at  about  4 :30,  as  follows.  "By  some  reason  or  other 
there  were  red  spots,  an  inch  in  diameter,  scattered  on  the  ground 
and  as  I  walked  toward  them  they  came  up  a  foot  high  and  so  thickly 
that  I  could  not  walk  through  them."  The  next  morning  he  explained 
that  he  had  been  working  at  blood  examinations  for  a  month. 


Fig.  16.    Experiments  on  dream.   Woke 

in  the  middle  of  the  contraction 

and  subject  had  a  dream. 

June  llth,  at  3:31,  during  a  contraction  period.  Subject  H  was 
questioned  concerning  dreams.  He  answered,  "I  had  a  dream,  but 
don't  remember  it."  The  experimenter  questioned  him  further  by 
saying,  "Do  you  remember  what  kind  of  dream  it  was?  Whether 
pleasant  or  unpleasant."  The  subject  replied,  "Somewhat  unpleasant ; 
I  may  recall  it."  After  a  few  minutes  he  said,  "I  may  describe  it 
partly:  How  do  you  want  it,  situation?"  "Yes."  "I  was  on  a 
mountain,  a  day's  journey  from  civilization ;  each  day,  before  I  went 
up  I  took  my  raincoat,  some  food,  etc.  After  I  got  there,  I  hung 
those  things  in  a  place  where  a  foreman  or  superintendent  kept  things. 
By  some  reason  or  other,  things  were  disappearing  there.  Whenever 
an  earthquake  occurred,  things  were  missed.  One  day  my  things 
only  disappeared,  and  I  was  coming  back  with  some  other  men,  but 
I  did  not  have  a  raincoat  and  got  soaking  wet,  but  tried  to  be  cheerful 
saying,  'Oh,  no  matter,  it  doesn't  make  any  difference',  and  I  came 
down."  Since  this  was  a  time  when  many  students  were  thinking 


IN  ITS  RELATION  TO  ACTIVITY  35 

of  going  home  for  the  vacation,  the  experimenter  asked  whether  it 
was  the  subject's  home  mountain.  "No,"  he  said,  "it  was  not  my 
home  state  mountain  nor  anywhere  I  can  recall.  That  is  all  there  was, 
thus  far."  The  subject  fell  asleep  and  had  more  contractions.  There 
was  no  dream  in  4 :00  to  4 :30  contraction  period,  when  asked  at  4 :22. 
At  5 :00  the  subject  dreamed  that  when  he  removed  the  tube  his 
throat  began  to  bleed  and  much  blood  spurted  out :  this  was  during 
the  contraction  period.  He  had  another  contraction  period  from 
6:10  to  7:10  A.M. 

Out  of  seven  experiments,  with  two  subjects,  on  four  nights,  there 
were  four  dreams  and  two  negative  answers,  in  the  contraction  period. 
No  dreams  were  discovered  in  the  quiescent  period. 

Thus  far,  the  observations  showed  that  there  was  greater  tendency 
toward  dreaming  during  the  contraction  periods  than  in  the  quiescent. 
Waygandt  states  that  starving  persons  dream  more  than  usual  in 
their  sleep.  (Carlson  '17.  P.  87.)  - 

CHAPTER  VII. 

CORRELATION  OF  THE  HUNGER  RHYTHM 
WITH  MOTOR  ACTIVITY. 

In  order  to  measure  efficiency  in  motor  activity  during  the  hunger 
contraction  and  quiescent  periods,  the  hand  dynamometer  was  chosen. 
Other  motor  tests  such  as  tapping,  steadiness,  co-ordination  tests,  and 
typewriting  were  used  with  three  subjects  for  a  period  of  three  weeks. 
They  were  found  to  involve  many  variables  among  which  the  effects 
of  practice,  fatigue,  and  varying  degrees  of  interest  were  especially 
prominent.  The  improved  Smedley  hand  dynamometer  proved 
the  best  measurement  of  the  maximum  of  grip.  There  was  no  per- 
ceptible influence  of  fatigue  or  lack  of  interest  when  experiment  was 
undertaken  at  intervals  of  two  minutes.  Adaptation  to  the  test  was 
provided  by  practice  for  several  days  by  Subjects  B,  C,  H  and  W. 

On  April  18th,  Subject  H,  without  luncheon,  swallowed  the  stomach 
balloon  and  the  experiment  was  begun  at  4:30  P.M.  In  order  to 
avoid  fatigue,  the  subject  was  to  pull  the  hand  dynamometer  only 
when  the  order  was  given.  The  experimenter  watched  the  record 
very  closely  and  when  a  contraction  or  a  quiescent  period  established 
itself  definitely,  she  gave  the  order  for  the  subject  to  be  ready  and 
then  to  pull  the  hand  dynamometer  which  registered  the  score  in 
terms  of  kilograms.  Care  was  taken  not  to  let  the  subject  know 
the  score  he  made  at  any  time,  but  he  was  told  to  do  his  best.  The 


36  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

measurements  were  made,  on  this  day,  at  one  contraction  period, 
which  appeared  between  5  and  5  :30,  and  at  a  quiescent  period,  between 
5  :30  and  6.  At  7  P.  M.,  after  the  subject  had  dinner,  it  was  resumed 
until  8  P.  M.  The  scores  are  presented  in  Table  III  with  the  averages 
andP.E.A's. 

The  formula  is  P.E..    =    — f      '  -     .6745 

\     N 

On  April  22nd,  Subject  H's  grip  power  was  measured  at  one  long 
contraction  period  which  lasted  for  50  minutes,  and  at  quiescent 
periods  and  also  after  dinner  for  45  minutes.  On  April  24th,  he 
started  this  experiment  at  9  A.  M.,  without  food  since  the  previous 
evening.  There  were  four  contraction  periods,  two  in  the  forenoon 
and  two  in  the  afternoon.  Altogether,  eleven  groups  of  measure- 
ments were  obtained,  one  of  which  was  taken  after  dinner.  Table  III 
contains  all  of  H's  scores,  the  averages  and  P.E.  's. 


IN  ITS  RELATION  TO  ACTIVITY  37 

TABLE  III. 

The  scores  of  hand  dynamometer  of  Subject  H  on  April  18th,  22nd  and 
24th.  The  scores  measured  at  hunger  contraction  periods  are  indicated  by 
stars.  The  calculation  of  averages  and  P.E.A'S  are  based  upon  the  added 
score  of  the  right  and  the  left  hand. 

R.  &  L. 
Time  Right       Left       Added       Average          6  P-E-A 

April   18, 
A  :30  P.  M. 


2.15  .65 

1.47  .57 

DINNER 
7:00  P.M. 


2.34  .64 

April  22, 
5  :00  P.  M. 

1.50  .72 


48* 

44* 

92* 

45* 

43* 

88* 

48* 

45* 

93* 

49* 

41* 

90* 

49* 

45* 

94*     91.40* 

48.5 

41 

89.5 

45 

43 

88 

49 

41 

90      89.17 

D  I  N 

N  E  R 

49 

44 

93 

50 

41 

91 

47 

40 

87 

50 

42 

92 

45 

42 

87 

46 

43 

89      91.50 

50 

41 

91 

50 

38 

88      89.50 

50* 

41* 

91* 

50* 

45* 

95* 

52* 

42* 

94* 

49.5* 

41* 

90.5* 

48* 

42* 

90* 

49* 

44.5* 

93.5* 

51.5* 

43* 

94.5* 

50* 

41.5* 

91.5*    92.5* 

50* 

42.5* 

92.5* 

50* 

42* 

92* 

50* 

44* 

94* 

50* 

42* 

92* 

49* 

43* 

92* 

49* 

43* 

92* 

48* 

41* 

89* 

51* 

42* 

93* 

50* 

42* 

92* 

51* 

42* 

93* 

49* 

42* 

91*     92.05* 

47 

40 

87 

46 

42 

88 

47 

41 

88 

46 

40 

86 

46 

42 

88      87.40 

D  I  N 

N  E  R 

46.5 

42 

88.5 

49.5 

40.5 

90 

50 

40 

90 

49 

40.5 

89.5 

46 

38.5 

84.5 

1.84  .44 

5  :30  P.  M. 


L.21  -25 

6:00  P.M. 

46  42  88 

47  41  88 

A6  Aft  S^i 

.80  .24 

DINNER 

6:45  P.M. 


38  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

TABLE  III.  (Continued) 

6  P.E.A. 


R&  L 

Time 

Right 

Left 

Added 

Average 

7:00  P.M. 

46 

37 

83 

47 

40 

87 

47 

39 

86 

^ 

47 

39.5 

86.5 

49 

39.5 

88.5 

49 

41 

90 

48 

38.5 

86.5 

47 

36.5 

83.5 

48 

36 

84 

47.5 

39.5 

87 

46 

39.5 

85.5 

47.5 

39 

86.5 

86.85 

43.5 

40 

83.5 

41 

39.5 

80.5 

43 

39.5 

82.5 

43 

39 

82 

44.5 

38 

82.5 

45 

37 

82 

44 

38 

82 

44 

37 

81 

42.5 

35 

77.5 

40 

34 

74 

42 

35 

77 

80.41 

April  24, 

10:00  P.M. 

51* 

42* 

93* 

51* 

41* 

92* 

50* 

40* 

90* 

91.67* 

49 

38 

87 

49 

39 

88 

48 

42 

90 

49 

40.5 

89.5 

88.62 

48 

37.5 

85.5 

48 

37.5 

85.5 

46 

39 

85 

48.5 

38 

86.5 

43 

36 

79 

46.5 

37 

83.5 

47 

35.5 

82.5 

46.5 

37.5 

84 

43 

37.5 

80.5 

46 

39.5 

85.5 

83.75 

47* 

41.5* 

88.5* 

48* 

40* 

88* 

49* 

39* 

88* 

48* 

39* 

87* 

48* 

41* 

89* 

49* 

40* 

89* 

88.25* 

46 

34 

80 

46.5 

39 

85.5 

45 

38.5 

83.5 

47 

39 

86 

48 

39 

87 

47 

37 

84 

46 

36.5 

82.5 

44 

37.5 

81.5 

44.5 

37.5 

82 

45 

39.5 

84.5 

83.65 

2.23  .36 


2.82  .57 


1.25  .49 


1.19  .40 


2.30  .49 


.69  .19 


2.07  .44 


IN  ITS  RELATION  TO  ACTIVITY  39 

TABLE  III.   (Continued) 

R  *  L 
Time  Right       Left       Added       Average          6  P.E.A. 

12:30  P.M. 


88.22*    2.21     .50 
1 :30  P.  M. 


2:30  P.M. 

47     41     88 
45     41     86 

47       AT.       00 

86.09     2.60     .53 

93.25     1.48     .50 
3 :00  P.  M. 


48* 

42* 

90* 

47* 

38* 

85* 

47* 

42* 

89* 

47* 

39.5* 

86.5* 

45* 

41*' 

86* 

47* 

43* 

90* 

48* 

38* 

86* 

48.5* 

43* 

91.5* 

47.5* 

42.5* 

90* 

47 

41.5 

88.5 

43 

41 

84 

44 

41 

85 

46 

38.5 

84.5 

47 

41 

88 

45 

41 

86 

41 

39 

80 

47 

41 

88 

45 

41 

86 

47 

43 

90 

47 

40 

87 

50* 

44* 

94* 

50* 

45* 

95* 

50* 

43* 

93* 

49* 

42* 

91* 

47* 

42* 

89* 

50* 

45* 

95* 

51* 

42* 

93* 

51.5* 

42* 

93.5* 

50* 

44* 

94* 

50* 

45* 

95* 

50* 

42.5* 

92.5* 

48 

41 

89* 

49 

41 

90 

48 

42 

90 

49 

42 

91 

49 

43 

92 

49 

41 

90 

47 

43 

90 

48 

41 

89 

49 

42 

91 

48 

42.5 

90.5 

48 

43 

91 

47 

44 

91 

50 

44 

94 

45.5 

44 

89.5 

50 

44 

94 

46 

41 

87 

49 

41 

90 

50 

43 

93 

44 

41 

85 

46 

39 

85 

45 

43 

88 

93.14*    1.90     .48 
2:30  P.M. 


90.25     .87     .19 
4:00  P.M. 


89.77     3.10     .63 


40  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

TABLE  III.   (Continued) 

R  &  L 
Time  Right       Left       Added       Average          <3  P.E.A, 

5 :00  P  .M. 


. 

R  &  L 

Right 

Left 

Added 

44* 

42* 

86* 

45* 

43* 

88* 

49* 

45* 

94* 

48* 

44* 

92* 

47* 

38* 

85* 

49* 

39* 

88* 

48* 

42* 

90* 

48* 

44.5* 

92.5* 

48* 

43.5* 

91.5* 

47.5* 

41* 

88.5* 

48* 

42* 

90* 

89.59*         2.66  .54 

DINNER 

7:00  P.M.  41  42  83 

46  42  88 

47  42  89 
46  36  82 

46  41.5  87.5 
44.5  40  84.5 
46.5  38  84.5 
43  40  83 

47  40.5  87.5 
45  43  88 

7:30  P.M.  44  43  87  85.82  2.35  .48 


IN  ITS  RELATION  TO  ACTIVITY  41 

On  April  19th  and  21st,  Subject  C  underwent  the  same  procedure. 
In  all,  there  were  obtained  five  groups  of  the  contraction  period 
scores,  three  quiescent  and  two  groups  of  the  after  dinner  scores. 
The  results  are  to  be  seen  in  Table  IV. 

TABLE  IV. 

The  scores  of  hand  dynamometer  of  Subject  C  on  April  19th  and  21st. 
The  scores  measured  at  hunger  contraction  periods  are  indicated  by  stars. 
The  calculation  of  averages  and  P.E.A'S  are  based  upon  the  added  scores  of 
the  right  and  the  left  hands. 

R  &  L 
Time  Right       Left       Added       Average          6  P.E.A. 


April   19, 
4  :20  P.  M. 


51* 

41.5 

92.5 

49 

41 

90 

50 

40.5 

90.5 

49* 

43* 

92* 

49* 

44* 

93* 

45* 

42* 

87* 

50* 

41* 

91* 

50* 

41* 

91* 

49* 

36* 

85* 

49* 

42.5* 

91.5* 

49 

40 

89 

48.5 

40 

88.5 

48.5 

39 

87.5 

45 

38 

83 

45 

36 

81 

47 

34 

81 

45 

39 

84 

48 

40 

88 

47 

37.5 

84.5 

47 

40.5 

87.5 

50 

39 

89 

49 

40.5 

89.5 

51* 

40* 

91* 

52* 

44* 

96* 

91.00  1.08  .42 


5:00  P.M.  49*          42.5*        91.5*         90.07*          2.70  .69 


5  :30  P.  M. 


86.04  3.04  .59 

6:00  P.M. 

93.50*          2.50  .12 

DINNER 

7:00  P.M.  47  36  83 

40  33  73 
45  37  82 

45  35  80 
43.5  33.5  77 

46  36  82 
46  33  79 

41  33.5  74.5 
46  36  82 
45  37  82 

8 :00  P.  M.  47  37  84 

44  36.5  80.5 

48  40  88 

48  35  83 

49  39.5  88.5 
49.5  38  87.5 

8:30  P.M.  50  38.5  88.5  82.03  4.43  .72 


42  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

TABLE  IV.  (Continued) 

R  &  L 
Time  Right       Left       Added       Average          6  P.E.A. 

April  21, 

4  :55  P.  M. 


5  :30  P.  M. 


R  &  L 

Right 

Left 

Added 

39* 

34* 

73* 

50* 

42* 

92* 

48* 

43* 

91* 

47.5* 

41* 

88.5* 

52* 

39* 

91* 

51* 

40* 

91* 

50* 

37* 

87* 

51* 

42* 

93* 

50* 

41* 

91* 

47 

38 

85 

50 

40 

90 

51.5 

37 

88.5 

51.5* 

40* 

91.5* 

51* 

35* 

86* 

50* 

35* 

85* 

53* 

36* 

89* 

51* 

35* 

86* 

50* 

36* 

86* 

48* 

38* 

86* 

50* 

40* 

90* 

50* 

38* 

88* 

49 

37 

86 

51 

39 

90 

48 

36 

84 

47 

36 

83 

45 

32 

77 

46 

35 

81 

47 

35 

82 

50 

36.5 

86.5 

45 

32 

77 

49 

36 

85 

48 

35 

83 

88.6*  5.77  1.30 

87.83  2.09  .81 


87.50*         2.11  .47 


85.75  2.68  .90 


6:00  P.M.  48  35  83  81.64  3.39  .86 

DINNER 
7:00  P.M. 


43 

33 

76 

49 

34 

83 

48.5 

34 

82.5 

50 

36 

86 

49 

35 

84 

50 

33 

83 

52 

33 

85 

49 

34 

83 

47.5 

37.5 

85 

45 

34.5 

79.5 

47 

32 

79 

47 

33 

80 

47 

33 

80 

50 

33 

83 

48.5 

33 

81.5 

44 

30.5 

74.5 

48 

33.5 

81.5 

47.5 

35.5 

83 

46 

36 

82 

48 

34 

82 

82.00  2.78  .52 


7:30  P.M.  48  34  82  81.07  2.74  .70 


IN  ITS  RELATION  TO  ACTIVITY 


43 


Figs.  17  and  18  present  the  curves  of  the  hand  dynamometer  scores 
of  the  two  subjects.  The  averages,  which  are  schematically  presented 
by  the  horizontal  dotted  lines,  are  higher,  without  exception,  during 
the  hunger  contraction  periods  than  at  the  preceding  or  following 
quiescent  periods.  Subject  C's  scores  at  the  contraction  periods  on 
different  days  were  added  and  vthe  average  taken  is  89.98  kilograms 
(P.E.A  =.55).  The  average  of  all  his  scores  at  quiescent  periods 
and  at  after  dinner  periods  are,  respectively,  85.64  kg.  (P.E.A 
.49)  and  81.84  kg.  (P.E.A  =  .40).  C's  average  at  the  hunger 
contraction  periods  is  4.32  kg.  higher  than  at  quiescent  periods,  and 
8.14  kg.  higher  than  after  dinner  periods.  Subject  H's  scores  on  three 
different  days  were  calculated  in  the  same  way.  The  average  of  his 
scores  at  contraction  periods  is  90.91  (P-E.A  =  .22).  The  average 
of  his  grip  power  at  quiescent  and  after  dinner  periods  are  respect- 
ively 87.11  (P.E.A  =  .28)  and  85.42  (P.E.A  =  =  .40).  This  in- 
dividual can  pull,  therefore,  at  the  time  when  the  hunger  contrac- 
tions are  present.  3.80  kilograms  more  than  when  his  stomach  is  in 
non-active  state,  and  5.49  kilograms  more  than  when  his  stomach 
is  rilled  with  food  or  is  digesting  it. 


rion  contraction 

a,  *.„.*, 


Figure  17. 

The  curves  of  the  hand  dynamometer  scores  of   Subject  C.    A  star   (*) 
indicates  the  hunger  contraction  periods  and  a  double  cross  (  ^  ) 
the  after-dinner   periods.     A   horizontal   dotted   line   in- 
dicates averages. 

The  above  experiment  proves  that  hunger  has  the  positive  effect 
of  augmenting  the  efficiency  in  motor  activity.  In  other  words, 
the  rhythms  of  the  hunger  contractions  and  tips  and  downs  of  fluctua- 
tion in  the  motor  efficiency,  correlate  with  each  other  very  highly. 


44 


AN  EXPERIMENTAL  STUDY  OP  HUNGER 


x  •>  u  u.  i  of 


bJO 
£ 


E* 


3      « 
"I 'I 

M-H     U,     C 

O    CJ-- 


3§~ 


o  as  z: 

aJ         O 


O    S  »— 
£          B 


0 


o§.S 


IN  ITS  RELATION  TO  ACTIVITY  45 


CHAPTER  VIII. 

CORRELATION  OF  .THE  HUNGER  RHYTHM 
WITH  MENTAL  ACTIVITY. 

The  fifteen  forms  of  Part  I  of  the  Thorndike  Intelligence  Ex- 
aminations were  selected  for  the  purpose  of  measuring  the  effect 
of  hunger  contractions  upon  mental  activity.  The  reason  for  this 
selection  was  (1)  that  these  tests  have  various  kinds  of  mental 
functions,  involving  many  types  of  materials  such  as  words, 
digits,  geometrical  figures,  etc.;  (2)  that  these  tests  are  sup- 
posed to  be  relatively  free  from  the  effect  of  practice ;  and  (3) 
that  there  are  fifteen  different  forms  of  tests,  the  relative  dif- 
ficulties of  which  have  been  determined.*  The  substitution  or 
association  tests,  with  different  sets  of  numerals  as  keys,  were 
first  tried  for  several  hours  each,  with  two  individuals,  and  it 
was  found  that  the  effect  of  practice  was  very  great  and  also 
that  equality  in  difficulty  of  the  keys  could  not  readily  be  ob- 
tained. Consequently,  this  substitution  test  was  abandoned 
and  the  Thorndike  intelligence  tests  were  taken  up. 

Each  form  of  the  tests  was  carefully  studied,  and  the  fifteen 
forms  were  put  in  such  an  order  that  the  same  kinds  of  tests 
should  not  be  given  in  succession.  In  giving  these  tests,  the 
following  two  problems  were  kept  in  mind :  First,  whether  this 
prolonged  hard  mental  work  would  affect  the  vigor  and  fre-' 
quency  of  the  hunger  contraction,  and  second,  whether  there 
would  be  any  change  in  efficiency  in  doing  this  kind  of  mental 
work,  according  to  the  presence  or  absence  of  the  hunger  con- 
tractions. 

On  May  15th,  Subject  C  came  to  the  laboratory  without  having 
had  anything  to  eat  since  supper  the  previous  evening.  At 
10  A.  M.  he  sat  before  a  well-lighted  desk  in  a  quiet  experimental 
room  and  his  stomach  activities  were  recorded.  The  experi- 
menter watched  closely  and  gave  him  an  order  to  begin  a  given 
form  and  when  the  time  was  up,  gave  the  direction,  "Even 
if  you  have  not  finished  test  ,  begin  test ."  At  the 

*  Thorndike,  Edward  L.;  Equality  in  Difficulty  of  Alternative  Intelligence  Examinations. 
Psychol.  Review,  1921. 


46  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

end  of  30  minutes,  which  is  the  maximum  time  allowed  for  one 
form  of  tests,  the  subject  was  permitted  to  rest  for  three  min- 
utes and  then  he  was  given  the  next  set.  The  forms  A,  B,  F, 
C,  G,  K,  D,  M,  H,  L,  I,  O,  E,  and  J  were  given  up  to  6  P.  M.  Form 
N  was  given  at  8  :05  P.  M.  after  the  subject  had  had  a  hearty  din- 
ner following  24  hours'  starvation.  In  the  early  part  of  the  morn- 
ing, in  spite  of  the  fact  that  nothing  had  been  eaten  for  over 
sixteen  hours,  the  stomach  was  practically  quiet.  There  was  a 
one-hour  quiescent  period  followed  by  a  tonus  period  at  11  A.  M. 
which  lasted  one  hour  and  dropped  into  another  long  quiescent 
period.  No  contraction  appeared  until  1 :20  P.  M.  when  there 
were  12  contractions  of  the  amplitude  of  2  inches  extending  over 
a  period  of  20  minutes.  One  hour  of  quiescence  followed.  At 
2  :40  a  period  of  3  inch  long  contractions  appeared  and  the  final 
hunger  period  came  at  4:30  and  lasted  for  30  minutes,  though 
the  amplitude  of  the  contraction  was  small.  After  dinner  the 
stomach  was  in  perfect  quiescence. 

The  accomplishment  of  Subject  C  on  the  tests  is  presented 
in  Table  V,  together  with  the  state  of  hunger  and  the  expression 
of  the  subjective  feeling.  Fig.  19  shows  the  curve  of  his  scores. 
The  contraction  periods  are  indicated  with  stars.  Two  of  the 
highest  scores  occurred  at  the  contraction  periods.  During  the 
period  when  the  subject  reported  feeling  of  fatigue,  the  stomach 
was  quiet  and  the  scores  were  relatively  low,  i.  e.  at  11  A.  M.  at 
a  quiescent  period,  he  reported,  "Heaven  knows  I  am  glad  to 
leave  that,"  and  his  score  was  125;  at  3  P.M.  in  an  quiescent 
period,  he  felt  "tired"  and  said,  perspiring,  "I  don't  want  to  do 
any  more,"  and  his  score  wras  111  ;  at  4  P.  M.  he  reported  head- 
ache, while  his  stomach  was  in  perfect  quiescence  and  he  scored 
120.  After  the  meal  at  7  P.  M.,  the  subject  felt  much  refreshed 
and  reported,  "Much  easier  to  work  now.  I  feel  I  can  do  ten 
times  better."  But  his  achievement  in  mental  work  was  low,  123. 
Special  fatigue  was  never  reported  during  the  contraction  periods 
when  mental  efficiency  was  greatest.  Fig.  22. shows  a  rapid  fall 
in  mental  efficiency  and  the  appearance  of  feelings  of  fatigue 
immediately  following  the  contraction  periods.  The  fact  that 
the  feelings  of  fatigue  are  not  responsible  for  the  effectiveness 
of  work,  is  indicated  by  the  low  performance  following  the  din- 
ner. The  evidence  indicates  that  the  hunger  contraction  goes 
hand  in  hand  with  maximal  performance. 


IN  ITS  RELATION  TO  ACTIVITY 


47 


TABLE  V. 
Thorndike  Intelligence  Examination 


May  15,  Subject  C. 


Time 

Hunger 

Correcte'd    Time 

Form 

started 

state        Score 

seore® 

taken 

A 

10:05  A.M. 

Quiescent 

123 

0 

123 

30  min. 

B 

10:38   "    " 

" 

123 

+4 

127 

30 

F 

11:12    "     " 

" 

125 

0 

125 

30 

C 

11:45    "    " 

M 

129 

-1 

128 

29 

G 

12:21    P.M. 

" 

129 

+2.5 

131.5 

30 

K 

12:55    "    " 

" 

127 

0 

127 

30 

D 

1:28   "    " 

Contraction 

142 

-4 

138 

27'  40" 

M 

2  :01    "    " 

Quiescent 

124 

+  1 

125 

30 

H 

2:40   "    " 

Contraction 

126 

-2 

124 

29'  30" 

L 

3:13    "    " 

Quiescent 

110 

+  1 

111 

29'  40" 

I 

3:48   "    " 

128 

+0.5 

128.5 

30 

0 

4  '21    "    " 

« 

117 

+3 

120 

30 

E 

4:57   "    " 

Contraction 

137 

0 

137 

30 

J 

5:30   "    " 

" 

131 

-0.5 

130.5 

30 

N 

8:05    "     " 

After  Supper 

122 

+1 

123 

30 

Subjective 
feeling 


"Heaven  knows 
I  am  glad  to 
leave  that." 


"Tired",        per- 
spiring, "I  don't 
want  to  do  any 
more." 
"Headache." 


"Much  easier  to 
work  now.  I 
feel  I  can  do  ten 
times  better." 


TtttA         £          T  C  (JKDM  HUIOEJ 


Contraction  Periods 


.Subjective 

feeling  u  .# 

Heaven  knows 
lam  glad  to 
leave  that" 


,. 
Tired" 

perspiring 
"I  don't  want  to 

do  any  more" 


Headache" 


9 

Much  easier 
now.  I  feel  I 
can  do  ten 
times  better 


Fig.  19. 

A  diagram  showing  the  curve  of  efficiency  in  the  mental  tests  of  Subject  C, 

together  with  the  hunger  contraction  periods  and  the  subjective 

feeling  reported.     A  star    (*)    indicates   the   contraction 

period   and   a   double   cross    (#)    the   subjective 

feeling  reported. 

*  Thorndike,  Edward  L.:   Equality  in  Difficulty  of  Alternative  Intelligence  Examinations. 
Psychological   Review,    1921. 


48 


AN  EXPERIMENTAL  STUDY  OF  HUNGER 


Subject  H  took  the  same  tests  on  June  9th,  beginning-  at  10  :35 
A.  M.  He  had  had  no  food  since  the  previous  evening.  The 
successive  order  of  the  tests  was  changed  so  as  to  bring  the 
earlier  half  of  the  whole  series  later  and  vice  versa,  in  order  to 
compare  with  the  records  for  C.  In  the  order  of  H,  M,  L,  I,  O,  E, 
J,  B,  F,  C,  G,  K  and  D,  thirteen  tests  were  given  up  to  6  P.  M. 
After  dinner,  at  7,  form  N  was  given,  while  the  last  test  was 


June  9,  Subject  H. 


TABLE  VI. 
Thorndike  Intelligence  Examination 


Time 

Hunger 

Corrected     Time 

Form 

started 

state 

Score 

score 

taken 

H 

10 

:35  A.M. 

Quiescent 

135 

-2 

132 

30  min. 

M 

11 

:08    "     " 

" 

125 

-(-1 

126 

30 

L 

11 

:43    "     " 

" 

145 

-1 

144 

30 

I 

12 

:19    P.  M, 

Contraction 

151 

+0.5 

151.5 

30 

0 

1 

:23    "     " 

" 

136 

+3 

139 

30 

E 

1 

:55    "    " 

M 

140 

0 

140 

30 

J 

2 

:30    "     " 

Quiescent 

148 

-0.5 

147.5 

28'  15" 

B 

3 

:12    "     " 

•< 

144 

+4 

148 

28 

F 

3 

:39    "     " 

* 

146 

0 

146 

29'  25" 

C 

4 

:10    "     " 

Contraction 

152 

-1 

151 

25'  45" 

G 

4 

:38    "     " 

Quiescent 

126 

+2.5 

128.5 

29'  13" 

K 

5 

:08    "     " 

Contraction 

147 

0 

147 

28'  10" 

D 

5 

:37.  "     " 

" 

148 

-4 

144 

26'  20" 

N 

7 

:00   "     " 

After  Dinner 

142 

+1 

141 

29'  35" 

A 

11 

:13    ' 

Contraction 

151 

0 

151 

29 

m  of 
ts 

H              T. 

I            O 

H 

Contraction    x x x- 

!  Periods 


Fig.  20. 

A    diagram    showing    the    correlation    of    the    hunger    rhythm    with    the 

efficiency  of    Subject   H   in  the   mental  tests.     A   star    (*)    indicates 

the  hunger  contraction  period. 


IN  ITS  RELATION  TO  ACTIVITY  49 

tried  at  11:13  before  the  subject  retired.  Table  VI  shows  the 
hunger  state,  the  scores,  and  the  time  taken.  Half  of  the  group 
were  finished  within  the  time-limit,  the  shortest  of  them  all 
being  25  minutes  45  seconds.  But  no  special  credit  was  given 
for  it.  Expressions  of  the  subjective  feeling  were  not  obtained 
in  this  case.  Fig.  20  shows  the  correlation  of  the  curves  of  the 
intelligence  test  scores  of  Subject  H,  and  of  the  stomach  activity 
which  was  drawn  from  the  measurement  of  amplitude  of  each 
stomach  activity  on  the  graphic  record.  An  examination  of  these 
curves  reveal  that  four  out  of  five  contraction  periods  were  ac- 
companied by  highest  test  scores,  144,  151.5,  151,  and  147;  while 
the  remaining  one  contraction  period  had  a  test  score  of  139, 
which  is  a  little  below  the  average,  142.5  (P.E.  --  6.43).  Study 
of  the  curve  shows  a  rapid  rise  in  efficiency,  with  the  onset  of  the 
contractions  to  a  maximum  at  about  the  middle  of  the  period. 
Accompanying  the  decrease  in  the  intensity  of  the  contractions 
to  the  quiescent  period,  is  a  similar  decline  in  the  efficiency  of 
the  mental  work.  The  two  curves,  in  fact,  are  nearly  parallel. 
Following  the  6  o'clock  dinner,  a  period  of  quiescence  was  fol- 
lowed by  a  gradually  increasing  stomach  activity  which  did  not 
culminate  in  acute  contraction  when  the  experiment  was  dis- 
continued at  11  :30  P.  M.  The  curve  of  mental  achievement  is 
a  close  parallel. 

In  order  to  test  further  the  correlation  of  the  subjective  feeling 
with  the  actual  efficiency,  form  D  was  given  to  Subject  C  on 
June  9th,  at  11  :55  P.M.  when  he  said  that  he  was  "tired,  having 
been  busy  until  so  late."  The  set  E  was  given  at  8:08  A.M. 
when  he  woke  from  sleep  and  felt  "Very  good."  Scores  were  142 
and  147  respectively.  Subject  H  repeated  this  experiment  on 
June  llth  and  took  D  at  11  :19  P.  M.,  E  at  7:35  A.  M.  He  scored 
145  in  D  and  148  in  E.  All  of  these  tests  were  given  during  con- 
traction periods.  Table  VII  shows  the  details.  During  the 
"tired"  periods,  the  scores  are  slightly  lower,  but  the  time  spent 
is  less,  that  is,  there  appears  a  tendency  to  hurry  the  work  with, 
probably,  no  loss  of  efficiency  per  unit  of  time.  This  finding  is 
in  harmony  with  the  other  studies  of  the  influence  of  feelings 
of  fatigue1"2. 

1  Thorndike,    Edward   L. ;    Educational   Psychology,   Vol.   III. 

2  Gates,   Arthur   I.;    Diurnal   Variations   in    Memory   and  Association.     Variations   in    Effi- 
ciency   during   the    Day    together    with    Practice    Effects,    Sex    Differences    and    Correlations. 


50 


AN  EXPERIMENTAL  STUDY  OF  HUNGER 


TABLE  VII. 
Thorndike  Intelligence  Examination 


June  9,  Subject  C. 

Time  Hunger 

Form         started  state        Score 

D         11:55    P.M.  Contraction     146 


A.M. 


147 


June  11,  Subject  H. 

D         11:19    P.M.    Contraction     149 


0 
-4 


7:35   A.M. 


148        0 


Corrected 

Time 

Subjective 

score* 

taken 

feeling 

142 

24'  25" 

"Tired     being 

busy   until   so 

late." 

147 

28'  30" 

''Very    good." 

145 

23  min. 

"Very  tired  from 

working  hard  a 

whole  day." 

148 

30 

"Feel  fine." 

The  amount  of  difference  in  achievement  in  the  Thorndike 
tests  between  contraction  and  quiescent  periods  may  be  illus- 
trated in  another  way.  The  Thorndike  Intelligence  Examination  tests 
were  given  to  the  medical  school  class  to  which  the  two  Sub- 
jects C  and  H  belonged.  Form  D  was  given  at  first  as  a  trial 
and  immediately  after  it,  form  E  was  taken.  Fig.  21  shows  a 
surface  of  frequency  based  upon  the  measurements  of  this  class 
of  eighty-two  graduate  medical  students  with  form  E.  The 
average  of  the  scores  of  the  total  class  is  117.5,  the  median  devi- 
ation (P.E.)  being  8.81  and  S.D.  11.77. 

Subject  C's  score  in  this  class  was  106.  This  was  before  the 
fifteen  forms  of  tests  were  given.  All  of  his  scores  in  the  tests 
taken  successively  later  on,  are  plotted  in  a  curve  in  Fig.  21. 
Subject  H  made  scores  114  and  116  in  forms  D  and  E  respectively, 
when  he  took  it  with  his  class.  All  of  H's  scores  are  on  the  dia- 
gram in  Fig.  22.  Fig.  23  shows  diagramatically  the  relative  posi- 
tion of  the  two  subjects  in  their  class.  C's  average  is  126.3, 
while  H's  is  144.2.  The  curve  for  Subject  C  is  the  same  as  in 
Fig  21.  H's  curve  was  altered  from  the  one  following  the  suc- 
cessive order  of  tests,  into  one  according  to  the  order  of 
tests  that  C  took.  This  changed  but  little  the  general  outline  of 
H's  curve.  The  variability  of  performance  is  so  great,  that  the 
scores  of  the  single  individual  range  over  half,  or  more  than  half, 
of  the  range  of  the  whole  class. 

Part  of  the  individual  variability  is  due  to  practice  and  to  the 
inequality  of  the  several  forms  of  the  tests,  although  correc- 


For  the  class 
Range    59  (83-142) 
S.  D.       11.77 


For  Subject  C 

41    (106-147) 

8.26 


For  Subject  H 
37.5  (114-151.6) 
11.0 


IN  ITS  RELATION  TO  ACTIVITY 


51 


tions  for  the  latter  were  made.  The  learning  curve  is  extremely 
irregular  and  Figs.  19  and  20  show  that  the  variations  are  cor- 
related with  conditions  of  the  stomach,  rather  than  with  the  de- 
gree of  practice.  That  the  shape  of  the  curve  was  not  caused  wholly 
by  the  inequality  of  the  tests  is  indicated  by  the  fact  that  the 


IT-"    "-"-"- 


/CO 


/3S 


J50 


r    no     //s    /so     12$  / 

Fig.  21. 

A  diagram  showing  the  surface  of   frequency  based  upon  the  test  scores  of 
the   class,   and  the  curve  of   the   successive   scores   of    Subject   C. 
A  star   (*)   indicates  the  scores  achieved  at  the  contrac- 
tion periods.     A  double  cross    (  ^ )    indicates 
the  scores  at  the  quiescent  periods. 


52 


AN  EXPERIMENTAL  STUDY  OF  HUNGER 


order  of  tests  for  Subject  H  was  the  reversal  of  that  for  Sub- 
ject C.  Their  achievements  varied  similarly  and  seemed  unques- 
tionably to  parallel  the  degree  of  activity  of  the  stomach.  The 
two  indication  marks,  a  star  (*)  and  a  double  cross  (#)  in  Figs. 
21,  22  and  23,  prove  that  in  all  curves  the  test  scores  are  high  at 
the  hunger  contraction  periods,  and  low  at  the  quiescent  periods. 


f*          yf        10          15"        JIQ         /OS"     //O      ~  11$      /20        JZ5~      /30        /«35"      JH-0        If-S      ISO 

Fig.  22. 

A  diagram  showing  the  surface  of  frequency  based  upon  the  test  scores  of 

the  class,  and  the  curve  of  the  successive   scores   of    Subject   H. 

A  star  (*)  indicates  the  scores  gained  at  the  contraction 

periods.     A   double   cross    (  # )    indicates   the 

scores  at  the  quiescent  periods. 


IN  ITS  RELATION  TO  ACTIVITY 


53 


The  foregoing  experiment  proved  that  hunger  augments  mental 
efficiency.  The  effect  on  fatigue  of  this  continuous  mental  work 
appeared  in  the  fact  that  in  the  case  of  Subject  C,  the  hunger  con- 
traction periods  were  much  depressed  and  did  not  take  normal 
frequency  nor  vigor,  though  this  was  not  so  marked  in  the  case 
of  H.  The  subjective  feeling  of  fatigue  correlated  very  closely 
with  the  quiescent  periods  and  the  low  efficiency. 


85 


/SO 


Fig.  23. 

A  diagram  showing  the  relative  position  of  the  scores  of  two  Subjects, 

C  and  H,  and  their  averages  in  the  surface  of  frequency  in 

relation  to  the  class  average. 


54  AN  EXPERIMENTAL  STUDY  OF  HUNGER 


CHAPTER  IX. 

THE  EFFECTS  OF  VARIOUS  STIMULI  UPON 
THE  HUNGER  RHYTHM. 

1.    THE  EFFECT  OF  MECHANICAL  STIMULATION. 

During  the  night  experiment  of  April  24th  the  experimenter 
twice  blew  the  stomach  balloon  to  see  if  there  had  been  any 
wreckage,  since  after  strong  contraction  periods,  the  respiration  pres- 
sure rhythm  became  so  low  that  it  extended  beyond  the  limit  of  the 
smoked  paper.  Each  time  when  the  tube  to  the  manometer  was 
disconnected  for  a  few  minutes  and  the  balloon  was  distended, 
there  appeared  on  the  record  a  few  stomach  contractions,  while 
the  stomach  was  quiescent  otherwise.  Curiously  enough,  the 
bodily  movements  appeared  simultaneously  with  these  contrac- 
tions. Further  study  of  this  phenomenon  was  taken  up  on  June  9th. 
At  4:15  A.M.,  while  Subject  C  was  asleep,  the  stomach  balloon 
was  disconnected  from  the  manometer,  and  wras  blown  up  to 
such  an  extent  as  to  bring  the  marker  one  inch  higher  in  posi- 
tion on  the  smoked  paper.  This  was  done  five  minutes  after  a 
long  contraction  period,  which  had  lasted  twenty  minutes.  This 
distention  of  the  balloon  was  immediately  followed  by  a  long 
contraction  period  which  lasted  45  minutes,  the  contractions 
numbering  43.  The  same  stimulus  was  given  at  5:15,  ten  min- 
utes after  this  long  contraction  period.  It  started  one  large  con- 
traction and  a  large  bodily  movement.  (See  Fig.  24.)  At  7:15. 
ten  minutes  after  a  strong  contraction  period,  blowing  the  bal- 
loon produced  a  one-inch  contraction,  and  a  fewT  wrigglings  of 
the  body.  Ten  minutes  later,  at  7  :26,  in  the  midst  of  a  quiescent 
period,  there  followed,  a  few  minutes  after  the  stimulus  was 
given,  one  contraction  and  a  body  movement. 

On  June  10th  this  experiment  was  repeated  with  Subject  H. 
After  a  strong*,  one-hour  contraction  period,  a  state  of  quies- 
cence set  in,  and  lasted  for  50  minutes.  At  6:20,  the  stimulus  of 
distending  the  balloon  was  given.  As  soon  as  the  apparatus 
started  to  mark,  it  showed  a  strong  contraction  period,  which 
lasted  for  30  minutes  ending  with  a  tetanus. 


IN  ITS  RELATION  TO  ACTIVITY 

Fig.  24.    A  and  B.     Effects  of  various  stimuli. 
Mechanical  stimulus  of   blowing  balloon. 


55 


A. 


B. 


56  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

Subject  H  was  once  more  tested  on  the  following  night,  June 
llth.  There  was  a  contraction  period  up  to  5:20  A.M.  which 
was  followed  by  a  tetanus,  and  a  long  quiescent  period.  After 
the  stomach  was  perfectly  quiet  for  40  minutes,  the  stimulus  was 
introduced,  at  6:05.  This  did  not  bring  about  any  result  until 
five  minutes  later  when  there  came  a  gradual  start  of  a  con- 
traction period.  At  7  :20,  at  the  end  of  a  vigorous  contraction 
state,  another  blowing  of  the  balloon  was  introduced.  Three 
minutes  after  there  was  a  contraction  and  a  few  bodily  move- 
ments and  a  few  minutes  later  the  subject  awoke. 

1"he  above  results  show  that,  out  of  seven  experiments,  two 
immediately  started  contraction  periods,  lasting  45  and  30  min- 
utes respectively ;  one  started  a  group  of  contractions  five  min- 
utes after  the  stimulus,  and  four  gave  a  few  contractions  and 
bodily  movements.  These  mechanical  stimuli  seemed  to  arouse 
local  reflexes  of  the  stomach,  which  may  be  controlled  by  the 
plexuses  of  Auerbach  and  Meissner.  About  the  same  time  that  the 
present  writer  had  found  these  results,  Carlson*  published  his 
results  wherein  he  concluded  that  mechanical  or  electric  stimu- 
lation of  the  lung,  the  gall  bladder,  the  heart,  the  urinary  bladder, 
and  the  entire  gastro-intestinal  tract  induces  skeletal  reflexes 
both  in  decerebrated  and  in  purely  spinal  preparations.  The 
bodily  movements  that  occurred  simultaneously  with  the  stom- 
ach contraction  seemed  to  prove  that  the  afferent  nerve  fibres 
of  the  viscera  make  reflex  connections  with  the  skeletal  motor 
system,  though  they  may  have  long  latent  periods  and  rapid 
fatigue,  which  indicate  a  complex  synaptic  system,  either  in  the 
spinal  cord  or  in  the  visceral  afferent  paths. 

Carlson  assumes  that  these  visceral  skeletal  reflexes,  at  least 
as  regards  the  extremities,  are  essentially  of  the  defensive  or  es- 
cape type.  It  suffices,  however,  to  state  that  the  present  experi- 
ment proved  that  the  mechanical  stimulation  produced  the  stom- 
ach contractions,  as  well  as  bodily  movements  in  man. 

2.    THE  EFFECT  OF  DRUGS. 

Papaverin,  an  opium  alkaloid  (C12H21NO4),  has  been  estab- 
lished, especially  on  the  continent  of  Europe,  as  having  the  ef- 
fect of  paralyzing  smooth  muscles,  such  as  those  of  the  stomach. 
Dr.  D.  Macht,  of  Johns  Hopkins  University,  has  extracted  the 

*  Carlson,  A.  J.;   American  Journal  of  Physiology.    Vol.    55,   P.   384,    1921. 


IN  ITS  RELATION  TO  ACTIVITY  57 

essence  of  this  drug  and  produced,  by  combining  it  with  other 
solutions,  such  as  alcohol  and  wine,  a  little  more  tasteful  drug, 
called  benzyl-benzoate.  These  drugs  are  used  to  stop  smooth 
muscle  contractions  of  the  stomach  or  intestines,  in  cases  of 
hemorrhage  or  vomiting.  In  the  present  study  these  two 
drugs  were  used  to  determine  (1)  how  they  affected  the  hunger 
contractions  during  sleep,  and  (2)  whether  relaxation  of  the 
stomach  muscles  influenced  the  gross  bodily  movements. 

On  April  13th,  at  10:30  P.  M.,  Subject  B  took  4  cc.  of  benzyl- 
benzoate  by  way  of  the  mouth,  together  with  y^  of  a  glass  of 
water  to  clean  the  mouth.  The  subject  went  to  bed  immediately, 
and  the  record  was  taken,  both  of  the  stomach  activity  and  the 
bodily  movement,  until  he  awoke  at  8  A.  M.  next  morning.  There 
was  a  long  tonus  period,  10:30  P.  M.  to  1 :30  A.  M.,  lasting  nearly 
3  hours,  during  which  tonus  waves  were  large  and  distinct.  The 
contraction  periods  of  1  :30  A.  M.  to  2  A.  M.  and  3:15  A.  M.  to 
3:30  A.M.  were  of  small  amplitude.  This  experiment  showed 
that  (1)  the  drug  gave  a  primary  stimulating  effect,  so  that  the 
tonus  waves  were  of  larger  amplitude ;  (2)  that  the  stomach  had 
a  longer  period  of  quiescent  and  tonus  states ;  (3)  that  the 
stomach  contractions  of  the  early  part  of  the  night  were  of 
smaller  amplitude  than  usual. 

Lest  other  components  of  the  drug  had  some  stimulating  effect,  the 
essence  of  the  original  Papaverin  was  tried  on  the  same  subject, 
on  April  20th.  From  10:30  P.M.  to  2  A.M.,  the  stomach  was 
very  quiet.  The  contraction  period  from  2  A.  M.  to  2  :30  A.  M. 
was  of  very  small  amplitude,  and  until  5  :10  A.  M.  the  stomach 
was  practically  atonic.  Three  contraction  periods,  5  :30  A.  M. — 
5  :45,  6 :30 — 7 ;  and  7 — 7 :30,  became  gradually  larger,  and  the 
final  one  was  of  the  amplitude  of  4.5  inches.  This  result  can  be 
interpreted  to  mean  that  the  drug  had  the  effect  of  keeping  the 
stomach  muscles  relaxed  until  5  :10,  and  after  that,  vigorous  con- 
tractions were  resumed  gradually.  The  bodily  movements  fol- 
lowed quite  the  same  distribution ;  when  the  stomach  was  atonic 
no  body  movement  could  be  seen.  There  was  no  way  of  knowing 
just  when  the  drug  had  been  absorbed,  or  had  begun  to  have 
effect.  It  would  be  of  value  to  introduce  this  drug  as  a  subcu- 
taneous injection  at  the  height  of  each  hunger  contraction,  and 
determine  how  long  it  will  have  effect  in  controlling  the  muscular 
movements  of  the  stomach. 


58  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

3.    THE  EFFECT  OF  CONSCIOUS  EFFORT,  THOUGHT;  SIGHT,  SMELL 
AND  TASTE  OF  FOOD. 

Oh  June  9th,  at  6  P.  M.,  when  Subject  H  had  contractions,  the 
experimenter  asked  him  to  try  to  stop  them.  In  spite  of  his 
effort,  large  contractions  continued.  Again  he  was  asked  to 
try  to  start 'contractions  bv  his  effort.  The  request  was  made  in 
the  quiescent  state,  but  the  subject,  of  course,  did  not  know  it. 
His  conscious  effort  made  no  difference  on  the  record.  The 
same  request  was  asked  of  Subject  C  on  June  10th,  at  7  :45  A.  M., 
before  breakfast.  This  brought  no  contraction  change,  not 
even  respiration  change.  We  can  be  quite  sure,  from  these  re- 
sults and  from  other  considerations,  that  the  stomach  contrac- 
tions, or  quiescence  are  quite  independent  of  conscious  control. 

A  few  minutes  before  6  P.  M.,  on  June  5th,  Subject  C  was 
asked  to  shut  his  eyes  and  think  of  delicious  dishes — a  dish  of 
hot  roast  beef  with  mashed  potatoes  and  green  peas,  salad  of 
fresh  lettuce  and  tomatoes,  and  hot  mince  pie — all  of  which  the 
subject  especially  liked.  This  thinking  was  done  while  the  stom- 
ach was  quiescent.  The  record  showed  no  effect.  On  June 
9th  Subject  H  was  asked  to  think  of  a  dish  of  sweet,  juicy  and 
delicious  cherries.  This  thinking  was  done  while  the  stomach 
was  in  contraction,  and  the  record  showed  no  effect.  A  dish  of 
cherries  was  then  brought  in,  which  the  subject  was  allowed  to 
observe  and  smell  as  much  as  he  liked.  No  change  appeared. 
However,  as  soon  as  the  food  particle  was  placed  on  his  tongue, 
salivary  secretion  gushed  out,  which,  together  with  some  of  the 
juice  of  the  food,  was  swallowed.  The  contraction  stopped  at 
once.  (See  Fig.  25.) 

In  the  morning  of  June  10th,  at  7:45,  when  Subject  C  awoke 
from  his  dream-experiment,  the  experimenter  asked  him  to 
think  of  a  dish  of  sliced  oranges  for  breakfast.  This  started 
no  contraction,  but  rather  brought  down  the  tonus  state  into 
still  lower  stomach  pressure  condition.  After  5  minutes  a  dish 
of  juicy  sliced  oranges  was  brought  in,  and  the  subject  looked 
at  them  and  smelled  them.  The  stomach  started  no  contraction 
from  these  stimuli. 

It  is  clear  so  far  (1)  that  conscious  effort  to  start  or  to  stop 
stomach  contractions  is  of  no  effect ;  (2)  that  the  thought,  sight 
or  smell  of  food  has  no  direct  influence  to  start  or  to  stop  the 
stomach  contraction ;  and  (3)  that  food  particles,  or  juice,  or 
even  some  amount  of  saliva  swallowed,  stops  the  stomach  con- 
traction. 


IN  ITS  RELATION  TO  ACTIVITY 


59 


Fig.  25. 

(A)    Thought  of  delicious   food,  hot  beefsteak  with  mashed  potatoes 

and   green  peas,   fresh   green   salad  with   tomato   slices,   and  hot 

mince  pie  with  cheese,  did  not  stop  contraction.    (B)  Actual 

taste  of  food  stopped  contraction  and  swallowing 

the  juice  through  the  esophagus  is  marked 

as  if  being  contraction. 

4.  THE  EFFECT  OF  NAUSEA  FROM  ROTATION. 
Dr.  Knight  Dunlap  has  devised  a  rotating  chair  on  which  a 
•subject  sits  and  can  be  rotated  at  the  desired  speed  to  the  right 
or  left  turn  by  adjusting  the  switch.  On  May  22nd,  Subject  C,  who 
had  had  no  luncheon,  sat  on  this  chair.  The  experimenter  waited 
until  the  tonus  state  appeared  on  the  record.  Ten  minutes'  ro- 
tation was  given  at  2:30  P.M.  It  did  not  bring  nausea,  but 
brought  the  tonus  state  of  the  stomach  into  perfect  quiescence. 
Thirty  minutes  later  another  rotation,  20  minutes  long,  was 
given.  The  subject  felt  dizzy  and  nauseated.  He  looked  pale 
and  perspiration  was  seen  on  his  forehead.  The  condition  of 
the  stomach  was  absolutely  atonic.  In  spite  of  the  fact  that 
usually  this  subject  had  two  strong  contraction  periods  in  the 
late  afternoon,  between  4  and  5,  there  appeared  no  hunger  period, 
not  even  the  slightest  tonus,  up  to  5  :30.  Rotation  seemed  to 
liave  had  enough  effect  to  depress  the  tonus,  and  the  contraction 
of  the  stomach.  The  physiological  phenomena  of  nausea,  the 
general  emotional  state  of  disagreeableness,  as  well  as  the  un- 
familiar situation  of  sitting  in  an  electric  chair,  may  each  have 
contributed  to  this  general  depression  of  the  stomach  activity. 


60  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

5.  THE  EFFECT  OF  ELECTRIC  SHOCKS. 

On  May  21st  Subject  H  came  to  the  laboratory  without  lunch. 
He  was  provided  with  a  wire  ring  on  a  finger  of  the  left  hand. 
and  a  metal  plate  on  the  right  arm,  which  wrere  parts  of  an 
electric  circuit  closed  by  a  switch,  which  was  controlled  by  the 
experimenter.  The  experimenter  waited  until  a  large  tonus 
appeared  before  pressing  the  button  of  the  switch.  In  the  middle 
of  the  upgoing  tonus  rhythm,  electric  shocks  were  given.  The 
tonus  waves,  however,  pursued  the  normal  course  without  being 
checked  by  the  shock.  This  was  repeated  at  another  tonus  period, 
with  the  same  result.  The  experimenter  expected  to  try  at  the 
contraction  periods,  but  the  subject  had  no  contraction  period 
that  day.  On  the  following  day,  Subject  C  went  through  the 
same  experiment.  The  result  was  similar  except  that  twice,  out 
of  ten  shocks,  tonus  waves  dropped  to  the  level  immediately  after 
the  stimulus. 

In  both  cases  the  subjects  felt  uncomfortable  because  of  re- 
ceiving shocks,  and  they  said,  "I  don't  like  that !"  There  was 
no  contraction  period  in  either  case.  Probably  it  was  this  emo- 
tional state  of  general  discomfort  and  fear  that  influenced  and 
inhibited  the  occurrence  of  the  contractions.  These  external 
electric  stimuli  seemed  to  affect  the  autonomic  nervous  system, 
and  produce  general  emotional  states,  which  inhibit  the  muscular 
activity  of  the  stomach. 

6.  THE  EFFECT  OF  PROLONGED  WORK. 

On  April  3rd,  at  9  A.  M.,  Subject  C  began  to  copy  from  an 
Italian  book,  which  he  did  not  understand.  He  had  had  no  food 
since  the  previous  evening.  He  typed  with  an  Underwood  ma- 
chine while  the  apparatus  was  recording  his  hunger  states.  Up 
to  1 :20  one  continuous  state  of  quiescence  persisted.  After  a 
few  minutes  of  high  waves,  quiescence  followed  and  lasted  for  2 
more  hours.  At  3  :30  eleven  contractions  of  2.2  inches  were  seen. 
At  5  P.  M.  the  work  was  stopped  and  the  subject  was  allowed  to 
go  to  sleep.  As  soon  as  he  fell  asleep,  hunger  contractions  of 
3^2  inches  in  height  appeared.  From  5  to  6  P.  M.  there  was  a 
continuous  series  of  strong  contractions,  which  numbered  52  in 
all.  In  the  normal  records,  this  individual  had  contraction  periods 
most  frequently  at  11  o'clock  and  1,  2,  4  and  5  o'clock,  while  in 


IN  ITS  RELATION  TO  ACTIVITY  61 

the  work  experiment,  all  the  forenoon  and  afternoon  contraction 
periods  were  eliminated.  The  subject  himself  said  that  he  did 
not  feel  hungry  at  all  during  the  work.  Prolonged  work,  when  it 
involved  feelings  of  fatigue  and  lack  of  interest,  perhaps  through 
correlation  with  an  emotional  condition,  tended  to  inhibit  the 
hunger  contractions. 

7.    THE  EFFECT  OF  READING  EXCITING  STORIES. 

1.  An  Interesting  Story.  On  May  9th  Subject  H  swallowed  the 
stomach  balloon,  and  then  read  "Moon  Calf"  from  9:30  to  6  P.  M. 
He  was  alone  in  an  experimental  room,  and  was  allowed  to  use 
the  chair  or  the  couch.    He  read  the  story  with  great  absorption, 
especially  the  part  of  the  book  from  the  climax  on  to  the  end. 
The  record,  registered  in  the  next  room,  showed  three  contrac- 
tion periods,  which  were  much  shorter  and  of  less  amplitude 
than  the  normal  ones. 

2.  Stories  of  Fear  and  Horror.     Edgar  A.  Poe's  stories,  "Fall 
of  the  House  of  Usher,"  "Murders  in  the  Rue  Morgue,"  "The 
Premature  Burial,"  and  "The  Pit  and  the  Pendulum"  were  se- 
lected for  arousing  the  emotion  of  fear  and  horror  in  the  sub- 
ject. From  1 :45  to  6  P.  M.  on  June  5th  Subject  C  read  these  stories. 
In  spite  of  the  fact  that  he  had  had  nothing  to  eat  since  morning, 
the  stomach  showed  no  contraction  until  4  :30,  when  very  weak 
contraction  waves  started.     On  the  other  hand,  deep  breathing, 
which  habitually  occurred  once  every  t\vo  or  three  minutes,  in 
this   individual,   was   so    much   deeper    that,   on   the    record,    it 
measured  twice  the  amplitude  of  the  usual  ones. 

3.  Sad  Stories.     On  June  9th,  at  9 :50  A.  M.,  the  experiment 
was  started  with  Subject  C,  who  had  had  nothing  to  eat  since 
the    previous    evening   at    supper.      The    selected    stories    were 
"Vanka,"  by  Turgenief,  "Hide  and  Seek,"  by  Sologub.  and  "The 
Death  of  Nell"  from  Dickens'  "Old  Curiosity  Shop."    The  record 
showed  that  there  \vas  general  depression  of  the  stomach  ac- 
tivities.    No  contraction  period  appeared  in  the  three-hour  ex- 
periment. 

Thus  far  the  results  showed  that  certain  types  of  reading 
brought  about  diffused,  non-discriminable,  and  general  emo- 
tional states,  which  tended  to  inhibit  the  full  swing  of  the 
automatic  movements  of  the  stomach. 


62  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

CHAPTER  X.  . 
CONCLUSIONS. 

The  present  experimental  study  brought  to  light  a  certain  number 
of  facts  that  show  the  extent  to  which  hunger  plays  its  role  as  a 
dynamic  force  in  the  activities  of  life. 

The  primary  cause  of  the  physiological  and  psychological  phenom- 
enon of  hunger  is  ascribed  to  a  certain  muscular  contraction  of  the 
stomach.  The  hunger  contractions  of  the  stomach  occur  from  3  to 
4  hours  after  a  meal  and  recur  at  intervals  as  long  as  the  stomach  is 
empty.  The  start  of  the  hunger  contractions  is  controlled  by  the 
intrinsic  nerves  and  is  independent  of  the  extrinsic  nerves  which 
have  only  regulatory  effects.  Thus  the  stomach  is  a  self-starting  organ 
and  yet  has  intimate  connection  with  other  vital  organs  and  glands, 
through  the  autonomic  nervous  system  which  maintains  the  general 
tone  of  the  organic  background  of  emotional  and  perhaps  intellectual 
life. 

The  effect  of  the  gastric  hunger  contractions  upon  other  physiolog- 
ical conditions  was  investigated  as  reported  in  Chapter  II.  Changes 
in  respiration,  vasomotor  flow,  and  salivary  secretion  were  studied 
in  relation  to  the  hunger  contraction  rhythm.  Especially  close  cor- 
relation was  found  in  the  case  of  the  salivary  flow,  which  is  one  of 
the  most  immediate  accessory  phenomena  of  the  hunger  contractions. 

That  the  sensation  of  hunger  occurs  synchronously  with  the  hunger 
contraction  of  the  stomach  was  assured  in  the  present  experiment 
with  four  subjects,  men  and  women,  normal  and  clinical.  This  fact 
may  be  interpreted  as  -showing  that  the  stimulus  from  the  gastric 
organ  affects  the  cortical  integration  centers  in  some  way  so  as  to  set 
up  impulses  toward  the  co-ordinated  action  of  securing  food. 

The  stomach  contractions  not  only  arouse  the  sensation  of  hunger 
but  prepare  the  whole  body  for  activity,  even  during  unconscious 
states.  The  experiments  on  bodily  movements  of  men,  infants,  and 
rats,  showed  that  bodily  movements  occur  simultaneously  with  the 
hunger  contractions,  while  in  the  quiescent  periods  very  few  bodily 
movements  occur.  This  was  especially  marked  when  the  subject  was 
asleep.  In  the  cases  of  the  infants  and  rats  the  periodical  recurrence 
of  bodily  movements  was  strikingly  regular. 


IN  ITS  RELATION  TO  ACTIVITY  63 

In  sleep  we  do  not  know  to  what  extent  the  visceral  stimuli  of  the 
hunger  contractions  affect  the  central  nervous  system.  The  states 
of  dreaming  and  non-dreaming,  however,  seem  to  indicate  something 
of  the  mental  status  of  a  sleeping  man.  The  investigation  of  the 
correlation  of  the  hunger  contraction  periods  with  the  dreaming 
periods  revealed  it  to  he  positive.  Though  we  are  sure  that  there 
are  also  other  factors  that  control  the  occurrence  and  nature  of  dreams, 
the  present  results  warrant  the  statement  that  men  dream  more  at 
the  hunger  contraction  periods  than  during  quiescence. 

The  augmentation  of  motor  activity  was  tested  by  means  of  a 
hand-dynamomoter  which  was  found  to  be  less  subject  to  the  effects 
of  practice  than  other  familiar  motor  tests.  The  results  showed  that 
at  the  hunger  contraction  periods  the  power  of  grip  is  greater  than 
at  the  quiescent  or  after  dinner  periods.  The  average  of  all  con- 
traction period  scores  compared  with  those  quiescent  and  after-dinner- 
period  scores  is  88.98  kg.  (P.E.A  ==  .55)  vs.  86.64  (P.E.A  ==  .49) 
and  81.84  (P.E.A  -  .40)  for  Subject  C  and  90.91  kg.  (P.E.A  : 
.22)  vs.  87.11  (P.E.  =  .28)  and  86.42  (P.E.  =  .40)  for  Sub- 

A.  A 

ject  H. 

A  further  experiment  to  measure  the  effect  of  the  hunger  con- 
tractions in  its  relation  with  mental  activity,  Chapter  VIII,  produced 
the  following  facts:  using  fifteen  forms  of  the  Thorndike  Intelligence 
Examination,  Part  I,  a  high  correlation  between  the  hunger  con- 
traction periods  and  test  scores  was  found.  These  tests  are  relatively 
free  from  the  effect  of  practice,  but  vary  according  to  the  presence 
or  absence  of  the  hunger  contractions.  It  seems  safe,  therefore,  to 
say  that  hunger  augments  efficiency  in  mental  work. 

Thus  far  the  experiments  were  directed  toward  measuring  the 
effect  of  hunger  upon  physiological  conditions,  the  sensation  of 
hunger,  bodily  movements  during  waking  and  sleeping  states,  motor 
activity  and  mental  activity.  The  next  group  of  experiments  had 
the  purpose  of  investigating  the  effects  of  mechanical,  chemical, 
conscious,  and  emotional  stimuli  upon  the  hunger  states. 

The  mechanical  stimulation  of  distending  the  balloon  in  the  stomach 
produced  a  group  of  contractions  accompanied  by  bodily  move- 
ments of  the  sleeping  man.  The  chemical  action  of  drugs,  benzyl- 
benzoate  and  papaverin.  which  have  relaxing  and  tonus-lowering 
influence  on  the  smooth  muscle  structures,  depressed  the  periodicity 
and  vigor  of  the  hunger  contractions.  Less  frequent  and  less  vigorous 
appearance  of  the  hunger  contractions  resulted  in  fewer  and  weaker 
movements  of  the  body  of  the  sleeping  man. 


64  AN  EXPERIMENTAL  STUDY  OF  HUNGER 

The  conscious  effort  to  start  or  to  stop  the  contractions  of  the 
stomach  had  no  influence  in  controlling  the  hunger  rhythm.  The 
thought,  sight,  smell,  and  taste  of  appetizing  food  failed  to  have  any 
observable  affect  upon  the  gastric  hunger  states.  These  facts  prove 
that  the  hunger  rhythm  is  not  a  matter  that  can  be  controlled  directly 
by  the  conscious  center  of  "will"  or  motive. 

The  nervous  system  that  regulates  the  tonus  and  the  rhythm  of 
hunger  contraction  is  very  sensitive  to  emotional  stimuli.  The  effect 
of  nausea  from  rotation,  electric  shocks,  and  fatigue  from  pro- 
longed work,  showed  that  as  the  consequence,  the  hunger  rhythm  is 
distorted  and  the  contractions  are  inhibited.  Reading  exciting 
stories  brought  about  emotional  situations  which,  irrespective  of 
whether  they  were  of  interest,  fear,  horror,  or  sorrow,  had  inhibitory 
effect  upon  the  hunger  rhythm.  Emotional  stimuli,  therefore,  affect 
the  autonomic  (especially  the  sympathetic)  nervous  system  which 
has  an  inhibitory  influence  upon  the  visceral  function  of  the  stomach. 

From  the  preceding  conclusions  of  the  present  experiment  it  is 
evident  that  hunger  is  not  merely  a  local  function  of  a  local  organ. 
It  involves  the  whole  organism,  and  it  stimulates  the  motor  and  mental 
apparatus  so  as  to  bring  the  organism  into  a  state  of  readiness  to 
secure  food.  Biological  consideration  of  the  hunger  behavior  of 
lower  animals,  permits  us  to  say  that  the  state  of  tension  of  the  whole 
organism  prepares  it  for  the  strife  and  struggle  against  the  enemies 
which  lie  between  it  and  its  food. 

Hunger  is  ontogenetically  and  phylogenetically  one  of  the  oldest 
phenomena,  appearing  in  the  first  day  of  the  infant  life  and  in  the 
first  days  of  the  unicellular  ancestor.  The  hunger  mechanism  is  one 
of  the  most  primitive  organs,  in  the  sense  that  its  activities  are  carried 
on  partly  by  automatic  activities  of  the  organ  without  extrinsic  nervous 
control,  and  partly  by  the  sympathetic  nervous  system,  which  is  said 
to  be  "a  direct  survival  of  that  diffused  type  of  nervous  system  which 
alone  is  found  in  the  lowest  animals  which  possess  nerves  at  all,  such 
as  some  jelly  fishes  and  worms.  It  serves  to  supplement  the  non- 
nervous  protoplasmic  activities  of  the  different  tissues  which  co-operate 
in  the  performance  of  the  work  of  the  several  organs."*  Yet  this 
most  primitive  mass  of  tissues  and  nerves  forms  the  vital  organ  for 
the  survival  of  its  owner,  and  gives  moreover  a  characteristic  organic 
background  to  the  entire  conscious  life.  What  Herrick*  expressed 
in  connection  with  emotions  in  general  is  found  here  to  be  applicable 

*  Herrick,  C.  Judson;   An  Introduction  to  Neurology.     1918,  P.   252,  290. 


IN  ITS  RELATION  TO  ACTIVITY  65 

to  hunger  also.  "In  normal  man  the  mechanisms  may  function  with 
a  minimum  of  cortical  control,  giving  the  general  tone  of  well-being 
or  malaise,  or  they  may  be  tied  up  with  the  most  complex  cortical 
processes,  thus  entering  into  the  fabric  of  the  higher  sentiments  and 
affections  and  becoming  important  factors  in  shaping  human  conduct." 

Thus  hunger  determines  not  only  the  inner  conditions  of  man, 
but  works  as  a  driving  force  for  the  projection  apparatus,  arms  and 
legs,  etc.,  to  act  upon  the  outer  world.  When  viewed  sociologically 
we  are  amazed  at  the  fact  that  the  most  complicated  events  may  be 
traced  back  to  the  simple  and  normal  craving  for  food.  In  the 
economic  world,  food  stuff  is  the  barometer  for  the  rise  and  fall  of 
the  cost  of  living. 

The  fact  that  hunger  can  not  be  voluntarily  controlled,  does  not 
mean,  however,  that  there  is  no  way  of  guiding  and  educating  this 
fundamental  force  of  human  life.  The  laws  of  adaptation  estab- 
lished in  the  studies  of  conditioned  reflexes,  modified  reactions  to 
stimuli,  substitution,  and  sublimation  find  their  application  here 
also.  Especially  in  early  childhood,  educators  find  opportunities 
to  direct  the  habit  formation  of  infants  according  to  the  law  of 
hunger  and  its  periodicity,  the  law  of  sleep  and  activity  periods 
in  relation  to  hunger,  instead  of  according  to  tradition  and  hap- 
hazard ways.  For  the  problems  of  work  periods  in  school  and 
other  occupations,  if  the  leaders  keep  in  mind  the  same  funda- 
mental laws,  they  can  utilize  and  co-operate  with  these  natural 
tendencies  for  activity  and  non-activity  periods.  Without  the 
realization  of  this  biological  readiness  of  the  organism  in  hunger 
which  has  been  hitherto  called  the  instinct  of  food-seeking,  short- 
sighted guidance  and  suppression  may  give  rise  to  riots,  revolu- 
tions, and  international  wars.  The  degree  to  which  we  are  able 
to  control  the  dynamic  force  of  life  depends  upon  the  extent  of 
our  knowledge  of  the  force. 


VITA 

The  author,  Tomi  Wada,  was  born  in  Toyamaken, 
Japan,  on  July  1st,  1896.  She  received  her  early  educa- 
tion in  Niigata,  Osaka,  and  Kobe,  graduating  from 
Kobe  Girls'  High  School  in  1914.  She  continued  her 
studies  in  the  English  Department  of  Japan  Women's 
University  in  Tokyo,  receiving  the  diploma  in  1917. 
She  was  a  student  at  Teachers'  College,  Columbia 
University,  from  February,  1918,  to  February,  1921, 
receiving  the  degree  of  Master  of  Arts  in  June,  1920. 
She  was  granted  the  Dean's  Scholarship  from  Septem- 
ber, 1918,  and  the  Graduate  Scholarship  from  Septem- 
ber, 1920,  .to  February,  1921.  During  the  summer  of 
1920  and  from  February,  1921,  to  February,  1922,  she 
was  a  laboratory  student  at  the  Johns  Hopkins  Hospital. 
In  the  summer  of  1922,  she  visited  psychological 
laboratories  in  Europe.  She  was  a  student,  at  Columbia 
University  from  February  to  June,  1922. 


OCT  241975 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 


BIOLOGY  LIBRARY 


TEL.  NO.  642-2532 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


INTERL1BRARYLOAN 

JAN  «  2  1993 


LD2lA-6m~l,'75 
(S3364SlO)476-A-32 


General  Library 
University  of  California 


